Editore"s Note
Tilting at Windmills

Email Newsletter icon, E-mail Newsletter icon, Email List icon, E-mail List icon Sign up for Free News & Updates

November 11, 2007
By: Kevin Drum

INSTINCTIVE PHYSICS....Thoreau, whose physics conference is not electrifying him at the moment, asks:

Would intelligent aquatic creatures with opposable thumbs ever develop Newtonian mechanics?

Answer: Sure, but they wouldn't have anything to write it down on, so they'd soon forget. In any case, Thoreau brings up this momentous topic as an excuse to observe that our natural surroundings influence our instinctive view of physics. For example:

With air resistance it's not at all obvious that gravity accelerates all objects at the same rate. It took a long time for these things to be figured out, after careful experiments in which different phenomena were separately quantified and/or minimized.

This is something that's puzzled me for a while. If you drop a rock and an olive leaf over a cliff, then sure, the rock will hit the ground first. And that might lead to confusion. But if you toss a big rock and a somewhat smaller rock over a cliff, they'll both hit the ground at about the same time. And frankly, the Greeks were plenty smart enough to have tried this. So why didn't they? And that's not to mention the jillions of folks in between Aristotle and Galileo who apparently didn't try it either. Or even Galileo himself, who didn't drop cannonballs off the Leaning Tower of Pisa, which would have been simple and easy, but instead used the cockamamie pendulum route to figure out how things worked.

And what about Avicenna and his contemporaries? They rooted around in territory that was close to Newtonian mechanics, but did they ever figure out that heavier objects don't fall faster than lighter ones? Or the Chinese? Supposedly they invented everything, but did they ever try dropping a pair of printing presses off the Great Wall?

Any historians of science out there? What's the deal with the apparent failure to perform such a butt simple experiment over the course of 20 centuries?

Kevin Drum 5:49 PM Permalink | Trackbacks | Comments (109)

Bookmark and Share
 
Comments

I'd actually say Gallieo's way of proving that ligther objects fall at the same rate as heavier ones is even simpler then throwing things off of towers. He just considered what would happen to a composite object, like if you attached a heavier rock to a lighter one to make an even bigger rock: it's heavier, so Aristotle says it should fall faster, but it also has the lighter rock attached to it, which should be trying to fall slower then the object as a whole, and slowing the thing up.

Even if the ancients distrusted experiment (which is how I usually see the slowness in contradicting Aristotelian physics explained), I never understood how Gallileo's simple reasoning never occured to anyone earlier.

Posted by: Simplicio on November 11, 2007 at 6:09 PM | PERMALINK

I think dolphins would have figured it out faster due to the 3-space of their medium.

In addition to seeing things float, they can see them fall. They can see gas bubbles rise AND get larger. They can jump out of the water and distinguish the different behaviors of objects in and out of the water.

But mostly, unlike us, they can far more easily observe the medium they are in. They know they need to breathe and they know where they need to travel in order to breathe. And they can see that they exhale a gas.

Posted by: jerry on November 11, 2007 at 6:12 PM | PERMALINK

We don't know if the ancient Greeks did or didn't think about falling objects, etc. Only about 20 percent of the ancient texts have survived to let us know what they thought about. About 80 percent of the manuscripts including those once housed at the Library of Alexandria have been lost to us, and others simply vanished with the fragmentation and Christianization of the Roman Empire. We've only learned in recent years, thanks to the discovery of an Archimedes text hidden under medieval prayers, that he had pretty much worked out the foundation of calculus. We do know that the scholars at Alexandria figured out that the earth is round, calculated its circumference to a fair degree of accuracy, figured out that the earth circles the sun, and understood that its axis is tilted and produces the seasons, etc.

Greeks, mind you, were not known at lab and field experimentalists. They were, however, big on the thought experiment. Perhapsm by sine nuracke if technology, we may find yet another old Green text in yet another old prayer book that can illuminate us further. I'm always optimistic on that score. Monastic scribes knew the value of paper, if not the ideas inscribed on them.

Posted by: e.R. Beardsley on November 11, 2007 at 6:13 PM | PERMALINK

It's always puzzled me even more given that, when you drop any flat object with a lot of surface area relative to its weight, it doesn't just fall more slowly -- it FLUTTERS, showing immediately that it's rubbing against something that is slowing it on the way down. And flat objects resist plowing head-on through water in exactly the same way. The only thing I can conclude is that scholars had too much respect for Aristotle, who was, I gather, a bit of a dunce when he put his mind to it.

And of course it also took humanity an incredibly long time to come up with something as obvious in retrospect as the concept of a numeral for "zero" -- and even mathematicians as sharp as Descartes and Pascal had trouble convincing themselves that the number of consecutive times a random event (such as a coin flip) has happened in one particular way doesn't reduce the chances that it will happen that same way the next time. Our minds just have some (probably psychobiological) blind spots -- which makes one wonder how many we're still contending with without even knowing it.

Posted by: Bruce Moomaw on November 11, 2007 at 6:13 PM | PERMALINK

Well, I'd guess it was due to the nonexistence of what we now think of as the generally accepted scientific method, which has at its heart eternally falsifiable theories and testing via repeatable experiments. Lack of those things may in turn be due, e.g., to supernatural world-view (even the early scientists -- the alchemists -- had supernatural aspects at or near the root of all their explanations) or the lack of basic mathematical tools (probability and statistics key among them).

(Hell, even today, large portions of the American population reject evolution, and others who should know better talk about "belief in" evolution.)

IIRC, it took what we now call the Enlightenment -- with its simultaneous rejection of supernatural explanations and maturity of mathematics -- to finally bring the physical sciences into their own.

Posted by: bleh on November 11, 2007 at 6:18 PM | PERMALINK

This website has some relevant information. There was a Byzantine named, Iohannes Philiponus, who in the Fifth Century A.D., recorded and possibly performed a Galileo-style experiment, as part of his commentary on Aristotle's Physics. According to this article, “the fact of the uniqueness of free fall is even more remarkable in the light of modern physics, because it requires that two fundamentally different quantities, inertia and passive gravitational mass, always be exactly proportional to one another.”

Posted by: The Conservative Deflator on November 11, 2007 at 6:19 PM | PERMALINK

"...which makes one wonder how many we're still contending with without even knowing it."

497. I won't bother relating how I arrived at that number since my reasoning defies too many of your primitive assumptions.

Posted by: Goran on November 11, 2007 at 6:27 PM | PERMALINK

The scientific method seems intuitively obvious to us today (well to some of us). Not so in the not really all that distant past.

Posted by: SW on November 11, 2007 at 6:28 PM | PERMALINK

The scientific method seems intuitively obvious to us today

Sadly, I don't think that's true. Many self-identified liberals push very well known and somehow respected causes that are very much not reality nor scientifically based. Many are based on unfalsifiable theories.

There was a discussion this week about this over at tpmcafe with Susan Faludi and Amanda Marcotte vs. a 17 year old. My brief reading showed the 17 year old completely pwned them both. (Amanda ended up seeking solace with her groupies where many piled on the 17 year old....) Kind of funny and certainly worthy of an analysis by Kevin.

Posted by: jerry on November 11, 2007 at 6:34 PM | PERMALINK

I think Conservative Deflator has it right-- it's really very peculiar to suppose that -all- matter will fall with -exactly- the same time dependence, regardless of mass or composition. And, to actually do the experiment, one needs to understand that, ideally, velocity will increase linearly with time-- easy enough for us to conceptualize with algebra, graphs and calculus- not so easy without them.

Posted by: MattF on November 11, 2007 at 6:34 PM | PERMALINK

According to this article, “the fact of the uniqueness of free fall is even more remarkable in the light of modern physics, because it requires that two fundamentally different quantities, inertia and passive gravitational mass, always be exactly proportional to one another.”

Let's assume that matter was formed of two independent kinds of mass, one value for inertia, and a completely unrelated value for gravity.

Even so, the mass of everyday objects is made almost entirely of two types of particles, Protons and Neutrons in similar ratios, and those particles are very similar to each other.

So even if there were two distinct types of mass, it stands to reason that ratios between them would be pretty nearly exactly the same for any conventional matter.

Posted by: Boronx on November 11, 2007 at 6:39 PM | PERMALINK

Aristotle was talking about motion through dense media, and said so. He said that the speed of fall through a medium is proportional to an object's mass as well as inversely proportional to the density of the medium.

He then confronted the question of motion through a vacuum (or "void"). He concluded that, in a vacuum, the speed of light and heavy falling objects would have to be the same. Then he went on to say that that is "impossible" -- hence, there can be no vacuum.

So it is reasonable to say that he was not very wrong about motion through a medium (water or air), and that he could not have been expected to create a vacuum.

His words:

These are the consequences that result from a difference in the media; the following depend upon an excess of one moving body over another. Therefore [bodies] will also move through the void with this ratio of speed. But that is impossible; for why should one move faster? (In moving through plena it must be so; for the greater divides them faster by its force. For a moving thing cleaves the medium either by its shape, or by the impulse which the body that is carried along or is projected possesses.) Therefore all will possess equal velocity [in a void]. But this is impossible.

It is evident from what has been said, then, that, if there is a void, a result follows which is the very opposite of the reason for which those who believe in a void set it up.


Posted by: JS on November 11, 2007 at 6:42 PM | PERMALINK

only when it became relevant to warmaking did people start studying gravity, velocity, etc. Before cannons, you didn't need it...

Posted by: gfw on November 11, 2007 at 6:42 PM | PERMALINK

...in which different phenomena were separately quantified...

This is the key point. Everyone rags on Aristotle, but forgets that he was basically correct. Lighter objects do fall slower than heavier objects. It is only in a vacuum that this goes away. The effect isn't linear and heavier the object the closer it gets to some maximum speed, but effect still holds.

The real world isn't in a vacuum, though, and there was no way to produce one back then. The big leap is separating the various effects from one another, imagining an airless environment and realizing that there was information to be gained that way.

Imagine someone today confronting Aristotle:

"But it is just air resistance slowing the lighter object; without air the fall the same rate."

"So? We have air. I am correct, lighter objects fall slower."

Posted by: Mark on November 11, 2007 at 6:47 PM | PERMALINK

That was really interesting JS. +1 Would read again!

Posted by: jerry on November 11, 2007 at 6:50 PM | PERMALINK

I was just guessing, JS gets the reward for actually knowing. I hadn't known that Aristotle actually took air resistance into account directly. Very interesting.

Posted by: Mark on November 11, 2007 at 6:52 PM | PERMALINK

So Aristotle's main problem was his opposition to the idea that a vacuum can exist.

In arguing against the possibility of a vacuum, he mentions (as discussed above) that light and heavy objects would have to fall at the same speed in it -- which he considers "impossible".

Interestingly, another argument he uses against the existence of vacuum is that Newton's first law would have to be true. Again, in Aristotle's words (arguing why a vacuum cannot exist):

Further, no one could say why [in a vacuum] a thing once set in motion should stop anywhere; for why should it stop here rather than here? So that a thing will either be at rest or must be moved ad infinitum, unless something more powerful get in its way.

(Words in square brackets inserted by me to introduce the context of the discussion)

One could say that Aristotle was that aquatic intelligent animal, and did not fail to think of Newtonian mechanics -- rather, he thought of it and rejected it simply because he thought there could be no vacuum. And reading the above, isn't it reasonable to believe that Aristotle actually made Newton's job easier -- once the notion of a vacuum was accepted?

Posted by: JS on November 11, 2007 at 6:57 PM | PERMALINK

While I think there are at lot of very good insights in bleh's comment, in my opinion (I'm not a historian of science) the scientific method largely preceeded, and fed the enlightenment. I think the enlightenment was more driven by science, than the reverse, although they did reinforce each other.

I think it is a very interesting issue, that our species had several advanced civilizations, none of which led the the scientific/technological breakout caused by the Europen version. The question of why it happened in one culture, and not another might have some profound implications if we could answer it.

Posted by: bigTom on November 11, 2007 at 6:58 PM | PERMALINK

Kevin -

Did you actually drop a big rock and smaller rock over a cliff and observe that they both hit the ground 'at about the same time'? No; you reasoned backward from Newtonian physics and an elementary knowledge of air resistance in order to determine what would happen.

The same was true among ancient societies. Why test something when you know it to be true - and when the countervailing evidence is actually rather ambiguous in nature?

There were many brilliant thinkers in the past, but a lot of them were, like bloggers, too busy to actually go out and seek evidence for self-evident truths.

(P.S. However, the Philoponus mentioned above did point to the phenomenon of water which falls from a great height: the mass of water becomes more elongated as it falls, thus proving that there is such a thing as acceleration. A pretty clever observation, that.)

Posted by: lampwick on November 11, 2007 at 7:04 PM | PERMALINK

Mark loses 10 points, for not distinguishing between fluid resistance and buoyancy.

Posted by: Bruce Wilder on November 11, 2007 at 7:12 PM | PERMALINK

I think the catch was that even if someone noticed two different-sized and -weighted objects falling at the same rate--which over 1,000 years had to have happened a couple of times even without deliberate experimentation--they'd have reformulated Aristotle's rule into one based on density. "Objects fall at speeds that are relative to their densities" or something like that. [i]That's[/i] the "intuitive" rule that's so hard to undermine without sophisticated experimentation. It's what I was certain was true until something like 5th grade when we dropped an air-filled ball and a heavier foam ball 2 stories in science class. Blew my mind when they landed at the same time.

Posted by: Adam on November 11, 2007 at 7:12 PM | PERMALINK

I've always been intrigued by that "moment" in the Enlightenment, when the common worldview shifted dramatically, toward a functional view of "natural causes".

The ancient texts suggest that an elite existed in the Hellenic-Roman world, who shared a similar worldview. Caesar and Cicero have a unmistakeably "modern" sensibility. German philologists in the 19th century thought they could identify the emergence out of religious superstition of that sensibility: they called it the "birth of tragedy" and associated it with the dramas of the golden age of Athens. The Greeks had had a Dark Age, after the fall of Bronze Age civilization, and so an obvious parallel was drawn to the Renaissance and Reformation leading to a re-emergence of modernity.

Steven J. Gould wrote about the Enlightenment shift, and insisted that it was an effect of empiricism, of testing hypotheses. But, I think Peter Gay has the better of it, in documenting how the modern sensibility took over from superstition in a single generation, and spread steadily across Europe. One moment high officials are earnestly burning witches, and in the next, the idea seems absurd to them, and the Royal Society is investigating the longitude.

Newton, as is now well-known, was himself caught betwixt -- the founder of modern physics was also a dedicated alcemist, whose alcemical reasoning remained mired in "meaning" even while he was able to dismiss demands that he explain the "why" of gravity to focus on the functional "how".

Posted by: Bruce Wilder on November 11, 2007 at 7:33 PM | PERMALINK


If Kevin has not read Galileo's "Dialogue Concerning the Two Chief World Systems" he really owes himself that treat. Strange as this may sound, it's a very entertaining book.

Now, about experiment versus what we might call "philosophy": the ancient Greeks were into geometry. Geometry has been called "the science of exact reasoning from inexact figures" for a reason. The most carefully-drawn sketch proves nothing in geometry; it's just an aid to visualization. The sketch is analogous to an "experiment". You can determine "by experiment" that a right triangle with sides of three cubits and four cubits will have a hypoteneuse of five cubits, but that's not quite the same as proving the Pythagorean Theorem.

Likewise, dropping rocks may be a pleasant passtime, but it's not the same thing as understanding motion. Does it matter whether you drop them in Athens or Alexandria? You can't know, unless you have a theory to begin with. Logic is what you need to "prove" anything about falling rocks; experiments are merely particular illustrations -- sketches, if you like.

Galileo certainly believed something like the above. When he has Salviati explain motion to Simplicio using geometric logic and not careful measurements, he is not renouncing "philosophy" in favor of "empiricism". He is propounding a new and improved philosophy.

-- TP

Posted by: Tony P. on November 11, 2007 at 7:41 PM | PERMALINK

Also, remember the Greeks seemed to be (from the records we have) big on "thought experiments" and "what makes sense" rather than experimentation. If their "expoeriment" in their heads goes one way, then that's the way the world works, as long as the result is arrived at by logical reasoning; it may be miles off the mark, but it "makes sense", so that's that. Actually going out and hurling rocks around the landscape would be belaboring the obvious, and is so, unneccessary.

Now, since later people thought Aristotle was well-nigh perfection incarnate, his ideas _must_ be right, so once again a primitive game of lawn darts is superfulous.

Conceptualy (sp?) it is the same as the fact I don't go around checking up on Bohr and his ilk - I trust they weren't pikers, so why waste the effort? Structurally, there is a world of difference, since those guys left notes of experiements and actual observations, and people _have_ recreated the situations to check the results. But Ibn Sina no more wasted effort to go throw rocks around to check up on Aristotle than I go ponder vulcanization before cross-country treks in case Goodyear missed something.

As to why no one before Gallileo did the experiment: He was the first guy to go "Wait a minute" and then go actually test it, ie he was a right bastard and general hooligan. As the recipiants of that little tantrum, we consider it obvious*, but at the time it was a little off-kilter, because you just didn't go questioning the utterance of Aristotle, True Lord and God of the World (considering all the theological wanking from his time to theirs, most guys were way less critical of Aristotle than God).

* I try to explain why zero is so freaking important, but my students sit their wondering what drugs I took to make me decide to waste classtime trying to make decimal notation sound like it means anything; never underestimate the ability of people to internalize even the most amazing things and go: "eh" *shrug* - heck, we have a certain ennui about transporters and they haven't even been invented yet.

Posted by: Phalamir on November 11, 2007 at 7:52 PM | PERMALINK

While he did not drop balls off the Leaning Tower of Pisa, he did more than just use a pendulum.

He also dropped balls of different weights down inclined planes. So, please put the pendulum myth to rest.

Also, per Wiki, one John Philoponus first, though non-experimentally, rejected Aristotelean ideas of gravity 1000 years before Galileo.

That said, in rejecting Kepler's planetary elliptical orbits because of the "perfection" of the circle, and other things, Galileo was surprisingly pre-modern in many ways.

As for Aristotle, et al, Greek "science," with the occasional exception like Archimedes and Eratosthenes, was "top-down," analytical only, with no desire to conduct actual empirical study.

Posted by: SocraticGadfly on November 11, 2007 at 7:59 PM | PERMALINK

Newton gave his lectures to an empty classroom. His physics was not accepted during his own time

Sorry, but that's nonsense. By 1700 Newton had a celebrity among literate Europeans comparable to Einstein's fame in our time. And scientific work on mechanics took up Newton almost immediately. By the 1690s much of the business of physics consisted in reformulating Newton's work in analytic terms and extending it.

Posted by: bza on November 11, 2007 at 8:16 PM | PERMALINK

Students are routinely taught that humans did not use experimentation until relatively recently in history (Galileo, Bacon, or whatever).

The idea that the wheel, bow and arrow, agriculture, sailing, etc. were developed without experimentation, without making and testing hypotheses, boggles the mind.

Posted by: JS on November 11, 2007 at 8:16 PM | PERMALINK

My gut tells me that matter is comprised of strings vibrating in 13 dimensions. There's no proof available; it's just a gut instinct. Call me silly.

Posted by: absent observer on November 11, 2007 at 8:24 PM | PERMALINK

It's very simple: This was military technology up to that point.

Add to that the Greeks did kill off their great thinkers at one point, and the slavery as replacement for technology issue... And human development was slowed.

Posted by: Crissa on November 11, 2007 at 8:29 PM | PERMALINK


I haven't seen anyone mention it, but it's clear that the math in Europe was very poor in Greek times. Algebra is needed at a minimum, and it didn't reach Europe (with its physical science foundation) in any useful form until about 1200 with Fibonacci.

Scientific breakthroughs in general were achingly slow until the last 300 years, with the feedback that technology provided.

Posted by: winner on November 11, 2007 at 8:29 PM | PERMALINK

I know this is off topic but I have to say something about it.

I think Steve Benen must NEVER watch Bill Moyers journal, because if he had, one of his post would be all the more horrible

Blaming the wrong president for an overstretched military

Bill Moyers was interviewing Jeremy Scahill, the guy who wrote that book, BLACKWATER: THE RISE OF THE WORLD'S MOST POWERFUL MERCENARY ARMY.

At one point Scahill tells Moyer that Blackwater was in New Orleans, Louisiana right after Hurricane Katrina and Scahill ask the Blackwater guards how much they were being paid per day. The answer was $200.00 a day but get this, Blackwater was making $900.00 per Blackwater guard in New Orleans? $900.00 a day?

How lovely those Bush unbid contracts must be, and with taxpayer money too, especially when you consider that if you're a US military member, you go to war with army you havebyt with wonderful things Blackwater has that regular army does not. NO armer plated vest for the average GI but Scahill said those Blackwater guys have everything.

I can remember a time when conservative voters knew EXACTLY what to do with war profiteers like Bush and Cheney, whereby you're meaningless to this administration if you're regular army, because unless you're some company able to contribute huge sums of money for campaign funds, that all you can expect as a veteran or millary member is for the GOP to promote a flag burning issues, because it's all hype and cost no money, it cost nothing and keeps Walter Reed out of news.

Republicans don't support the troops, they support private secrety contractors, and they do with hard earned taxpayer money.

Why can't we ask Dems candidates the really important question? Like Hillary, are you going to keep all those private security firms in Iraq and pay them what Bush is paying them.

I'm sure Josh Marsahll and Kevin Drum will tell us how the glass is half-full when Hillary talks about how important the private security firms are to our vital national interest.

It was bad when Bush did it, but Kevin will love it when Hillary starts funding Blackwater.

Posted by: Me_again on November 11, 2007 at 8:32 PM | PERMALINK

You can't prove a negative, Kevin.

That is, you can't say that for all that time a simple experiment like this was not done. What you can say is that no one did the experiment and then proceeded to write about it.

So, let's do a little thought experiment ourselves. Why would some do the experiment and NOT write about it?

Easy. Because they could not explain the principal behind the action.

Posted by: Dicksknee on November 11, 2007 at 8:33 PM | PERMALINK

It was all a matter of what was useful for the times: experiments seek to find out what the experimenters think will be found. The modern era of science where millions or billions of dollars are spent just looking into things that may or may not happen under certain circumstances is very new in the scheme of things. Romans who tossed things at barbarians knew to toss heavy rocks of various weights rather than pillows, knew not to load a catapult with large flat ones, but did know to use packets of gravel now and then. And the probable existence of a vacuum didn't really bother anyone until carpets were invented. And the dolphins don't need thumbs because they don't give a crap about getting Mario to jump onto mushrooms. They swim and eat and play and avoid sharks while we try to design better mattresses and pants.

Science is a piggybacking beastie. Medicine has progressed from four humours and wombs that attach to the brain toward soap and viruses and scanning machines that determine which parts of the liver died from those mushrooms. Astronomy has gone from the gods' wrath or honor to navigation to heliocentric models to dark matter and astronomical units and new planets. And it's because we're writing it all down and demanding usefulness, not because we're that much better than our ancestry at seeing what's before our eyes.

Though I have to admit, those four humours can certainly explain the social workings of most people I know.

Posted by: jon on November 11, 2007 at 8:34 PM | PERMALINK

Obvious stuff that hadn't occurred to anyone like the wheel and how long did that take? Then once they figured that one out, how long did it take to figure out you could use the same wheel to do all sorts of other stuff from simple transport to generating power (like the grinding mill).

I think this is the root of what I'll call Paulo Law #1: Once something is known it is obvious but until then we are oblivious to its possibility.

I know others have inferred such a possibility but see paulo law #1.

Posted by: paulo on November 11, 2007 at 9:06 PM | PERMALINK

If you do drop two different objects from the Tower of Pizza, or from the roof of your school, you will find that they reach the ground at the same time -- but only if your exprimental apparatus is very rough (essentially, eyeballing the objects). If you use the most precise technologies available, you will find that Aristotle was correct -- they do not arrive at the same moment.

Ah yes, the physics teachers say -- that's because of the different effects of air resistance. Yes, that's right. And that's precisely what Aristotle was talking about.

And guess what, the stone vs. feather experiment (which every live human being has performed in one way or another) is indeed the relevant one here. If you use two heavy (but different) objects, the difference in times of fall will be so minute that you will be fooled into thinking that they are equal. But they are not (again, in air).

Again, Aristotle's error here was not what it is commonly thought to have been. Rather, it was his rejection of the idea that a vacuum can exist (where the speeds would indeed have to be equal, as he himself said).

Posted by: JS on November 11, 2007 at 9:26 PM | PERMALINK

Wasn't the original use of the wheel to throw pots, and not until much later is there evidence that it was used for transportation?

Besides the best lines in the original thread ("does this speculation have a porpoise? Dolphinately..."), I think Kevin's question is better than its implication: sure, critters that live in water would be more likely to figure out resistance than those of us who live in the air.

But it might be a humbler question to ask -- what do they know, that we don't? And then the less humber question: how can we find that out?

It is so common that we don't even notice how when an invader shows up, they discard or replace whatever it was that the autochthonous folks were doing: so Europeans showed up on America's woodland coast with diseases that killed off farming communities, then decided that all those carefully tended fields were God's gift to 'em; moved on to the American plain, killed off the buffalo, and then imported cattle...

And that's just within one species in a shared environment. How much more do we miss when we're underwater, or when we get out into space? Throw in time as a factor (can we even know how life forms with a billion year cycle act?), and ya get a bit less cocky talking about scientific "laws".

JS is right -- there were LOTS of experiments through human history. Folks who lived 100k years ago were as smart as we are, they just had less accumulated knowledge to work with. The guys 5,000 years ago who sat around a big fire blowing prayers into hollow reeds to make bright copper flow out of the rocks they'd set on the coals, cuz they could shape the soft stuff, they had SPECIFIC prayers they said -- and argued about how effective they were, too. "It's the BOO-yah that makes Vulcan happy, I'm telling you...... no, no, you have to do the three hour moaning or the BOO-yah chorus won't work."

Maybe the real story of human progress isn't so much what we've managed to learn, it's all the bullshit that we've managed to forget.

Posted by: theAmericanist on November 11, 2007 at 9:37 PM | PERMALINK

It only seems "butt simple" because it has already been done. This is what is known as the "hindsight bias," and it is prevalent in all fields.

Posted by: Andy on November 11, 2007 at 9:42 PM | PERMALINK

"Aristotle was talking about motion through dense media, and said so. He said that the speed of fall through a medium is proportional to an object's mass as well as inversely proportional to the density of the medium.

"He then confronted the question of motion through a vacuum (or 'void'). He concluded that, in a vacuum, the speed of light and heavy falling objects would have to be the same. Then he went on to say that that is 'impossible' -- hence, there can be no vacuum."

I rest my case. The man was a dunce.

Posted by: Bruce Moomaw on November 11, 2007 at 9:47 PM | PERMALINK

By the way, does anyone remember that in 1971 -- at the very end of Apollo 15's three 7-hour moonwalks (which were really the first moon "drives", for miles along the surface, with the TV camera, pannable and zoomable by an Earth cameraman, going along for the ride) -- James Irwin held up a big feather in one hand and a rock hammer in the other and dropped them at the same time to demonstrate Galileo's principle? Sure enough, they fell at exactly the same rate (leisurely, since it was the Moon) and hit the ground simultaneously a couple of seconds later. I always thought that was far neater than Alan Shepard's jackass golfing stunt on the Moon on Apollo 14.

Posted by: Bruce Moomaw on November 11, 2007 at 9:52 PM | PERMALINK

Why didn't they do experiments? Consider these two factors:
1) An important part of being a natural philosopher is that you weren't doing hard labor. Instead you had the privilege to sit and think. An experimental program is hard, physical work and takes a long time.

2) Measurement was crude, error-prone, and difficult. These experiments are simple and give clear results today because of precise measurements. Stopwatches, strobe lights, photographs, scales, etc are high technology.

Posted by: Jim Lund on November 11, 2007 at 10:13 PM | PERMALINK

"But it might be a humbler question to ask -- what do they know, that we don't? And then the less humber question: how can we find that out?"

Is the current physics paradigm really objective? For one thing I don’t see that three dimensions are an adequate description of space. They are nothing more then the coordinate system of the point the three lines cross. While it is as necessary to have some frame of reference to define space as it is necessary to have a starting date for a calendar, it is still an arbitrary point of reference. The fact is that any number of such points and frames can be used to define the same space. Competing frames of reference and the systems of organization they represent are the cause of conflict. You might say Arabs and Israelis use different coordinate systems to define the same space. This is largely the basis of Chaos Theory, where the rules may be determined, but the outcome cannot be predicted because intersecting processes yield unpredictable results, even, as experiments with cellular automata have shown, where it is feedback within the same initial structure. While any given map of space may be three dimensional, the reality is infinitely dimensional.

Is time a dimension, or process? Consider; If two atoms collide, it creates an event in time. While the atoms proceed through this event and on to others, the event goes the other way. First it is in the future, then in the past. This relationship prevails at every level of complexity. The rotation of the earth, relative to the radiation of the sun, goes from past events to future ones, while the units of time/days go from being in the future to being in the past. To the hands of the clock, the face goes counterclockwise.

So which is the real direction? If time is a fundamental dimension, then physical reality proceeds along it, from past events to future ones. On the other hand, if time is a consequence of motion, then physical reality is simply energy in space and the events created go from being in the future to being in the past. Just as the sun appears to go from east to west, when the reality is the earth rotates west to east.

With reality as energy just moving around, previous information is constantly being recycled by and giving structure to the present, as the energy by which it is recorded continues on its path. Rather then the straight line of a dimension, time is a loop, where the new is being woven out of strands pulled from the past. The result is also a state of constant chaos, since it is energy from conflicting frames that often comes in contact. (Energy in the same frame is subject to entropy though.)

Time as consequence of motion means it has more in common with temperature, then space, which certainly is not intuitive, but it is logical, since they are both descriptions of and methods for measuring motion. Time as dimension is intuitive. It's called narrative.

Using time as a dimension is like dissecting an organism. It lays everything out there for you to look at and poke and examine, but it’s rather lifeless. What if there is no dimension of time and reality really is just that ethereal energy radiating and clumping in space, with history and all the intellectual structure we attach to it as nothing more then the metaphorical tail of a comet. Is it any wonder that the more we poke at it, the more illusionary it all seems?

Rather then dimensions being reality, they are a crude tool for prying it apart. Math is a model of reality, not the ideal form of it.

This model defines life as well. The elemental awareness is attached to the energy and moves forward in time, but our intellectual comprehension is information that is constantly receding into the past. Ultimately we are cells of a larger organism that is constantly moving on to the next generation and shedding the old like dead skin. It is our individual lives that start in the future and end up in the past.

Posted by: brodix on November 11, 2007 at 10:30 PM | PERMALINK

Why don't you try doing something as butt simple as reading a book? Somehow, I have the feeling you'd have a hard time you'd have a hard time doing something as butt simple as formulating Newton's law of gravity. That's just one man's opinion, of course.

Posted by: Alan Vanneman on November 11, 2007 at 10:34 PM | PERMALINK

Paulo Law #1: Once something is known it is obvious but until then we are oblivious to its possibility.

I love this law. Two weeks ago I filed for a patent to solve a HUGE problem. My attorney has warned me of the difficulties of getting a patent granted. One reason patents are rejected is that the product is deemed an obvious solution to the problem.

My answer is that if it is SO OBVIOUS, why isn’t anyone doing it?

Posted by: emmarose on November 11, 2007 at 10:42 PM | PERMALINK

Its quite simple, life is created in reverse.

Posted by: Ya Know.... on November 11, 2007 at 10:43 PM | PERMALINK

Several commentators described Aristotle's rejection of the existence of void as if it were some sort of mistake. But since we're talking about fundamental physics here, I think it's fair to point out that absolute void is not found in our universe. Quantum physics says that space is completely chock full of various fields and with them all sorts of virtual particles.

Not that Aristotle had any notion of such things. But he did know and proved that it is impossible to measure the length of a moving object - which is akin to the insight of quantum mechanics that you cannot know the momentum and the position of a particle simultaneously with perfect accuracy.

Posted by: lampwick on November 11, 2007 at 10:46 PM | PERMALINK

Create a whole being and let nature figure out the rest.Its why we dream.

Posted by: Ya Know.... on November 11, 2007 at 10:46 PM | PERMALINK

everal commentators described Aristotle's rejection of the existence of void

I Disagree, if the big bang was the beginning and our universe expands in size, as in an explosion, we can only exist in a void.

Posted by: Ya Know.... on November 11, 2007 at 10:49 PM | PERMALINK

I rest my case. The man was a dunce.

Perhaps so -- but only because he believed that "nature abhors a vacuum", not because his understanding of falling bodies was false.

By the way, Aristotle's discussion of falling bodies was an incidental point he made in passing in his broader examination of whether a vacuum can exist, which was what he was really interested in. And he mentions other Greek philosopher / physicists who were on both sides of that question -- some clearly accepting the existence of void. (It's not clear if the others had also considered the speed of falling objects, however).

His discussion of void is quite fascinating, and not that dissimilar from later discussions of the existence of ether (more dunces right up to the 20th centure, you will probably say).

Bottom line: The only experiment that would have been meaningful in testing Arstotle's arguments on this subject would have required the creation of a vacuum (something that didn't happen until the 17th century). No, it was not a matter of dropping two stones from a high point, and he knew that.

Posted by: JS on November 11, 2007 at 10:49 PM | PERMALINK

Aristotle thought without resistance a body would fall at the same speed. IE a Vacuum, IE space. IE the big bang. IE VOID.
Nature, on Earth Abhors a vacuum, Our universe, however, depends on it.

Posted by: Ya Know.... on November 11, 2007 at 10:54 PM | PERMALINK

Xeophanes:

"The gods did not reveal from the beginning
All things to us; but in the course of time
Through seeking, men find that which is the better.

But as for certain truth, no man has known it,
Nor will he know it; neither of the gods,
Nor yet of all the things of which I speak.
And even if by chance he were to utter
The final truth, he would himself not know it;
For all is but a woven web of guesses."

Posted by: Dilbert on November 11, 2007 at 11:05 PM | PERMALINK

Wasn't the real leap that Galileo made the formulation of theory in the form of algebra, and the testing of those formulae via experimentation? It was the combination of both these ideas that was revolutionary. If you restrict your efforts to theory that is not precise mathematics, or don't challenge your theories with precise measurements/predictions then you won't get very far.

Now Newton was primarily a first class mathematician. His motivation was to solve physics problems, but he was forced to invent of a large body of important mathematics.

The problem with most modern science, is that it has become so math heavy, that it is inaccessable to >99% of the population. Fascination with the natural world, and willingness to work hard in the pursuit of knowledge are no longer sufficient to make an aspiring scientist successful. Great talent, and effort studying advanced mathematics is now a prerequiste. I wonder how many of the great scientists of past centuries would be able to make it today.

Posted by: bigTom on November 11, 2007 at 11:07 PM | PERMALINK

All that exists is A-toms and empty space; [void] the rest is just opinion -Demcritus of Abdera

Posted by: Ya Know.... on November 11, 2007 at 11:08 PM | PERMALINK

3,000 years ago,the Egyptians discovered that Crocodile dung could be used as birth control. Would you like to have been a member of the control group until they got the ammount right?

Posted by: R.L. on November 11, 2007 at 11:09 PM | PERMALINK

The problem with most modern science, is that it has become so math heavy, that it is inaccessable to >99% of the population. -BigTom

All numbers are unfinite.

Posted by: Ya Know.... on November 11, 2007 at 11:09 PM | PERMALINK

*infinite IE PI

Posted by: Ya Know.... on November 11, 2007 at 11:10 PM | PERMALINK

Mankind shall not ever find the truth of his beginning thru infinite numbers or large hadron colliders.

Posted by: Ya Know.... on November 11, 2007 at 11:15 PM | PERMALINK

It's like WMD in Iraq. Everyone knew Iraq has WMD.

Actually testing (inspectors) is threatening and has to be stopped.

Of course a heavy rock falls faster than a slow one. Why be an outcast?

Posted by: tomtom on November 11, 2007 at 11:24 PM | PERMALINK

The question of why it happened in one culture, and not another might have some profound implications if we could answer it.

Posted by: bigTom on November 11, 2007 at 6:58 PM | PERMALINK

Try reading Guns, Germs, and Steel by Jared Diamond.

Posted by: Michael7843853 G-O/F in 08! on November 11, 2007 at 11:57 PM | PERMALINK

It's a legend that Aristotle and the Greeks believed that the weight of objects determines the rate of fall. As other commentors have pointed out, not only is it due to resistance of the medium, it's also due to the *density* of the item. A simple thought experiment (of the kind beloved by the Greeks) illustrates this. Imagine two rocks of equal weight falling side by side. Move them closer and closer until they touch but aren't attached. Then attach them with weightless glue so that they become one rock. Does this rock, now twice the size of the individual rocks, suddenly fall twice as fast? No -- because the new rock has the same density as the two smaller rocks. It falls at the same speed.

Posted by: santamonicamr on November 12, 2007 at 12:03 AM | PERMALINK

The Greeks don't trust the sublunary world; it's mutable and inconstant and not quite real. Thus, any experiment you carried out on the earth would be worthless. To test things properly, you either have to go out beyond the sphere of the moon, where things are perfectly unchanging and regular and work properly, or you have to sit around doing thought experiments. (Because the intelligible world *is* trustworthy.) And going past the sphere of the moon isn't really a practical option, plus they don't have the same kind of matter up there anyway -- the four elements only extend to the orbit of the moon -- so the results you got up there wouldn't generalize down to here. (There are no universal laws of physics.)

That is the reason. Change is bad, motion is bad, time is bad, finitude is bad, passivity is bad, so the terrestrial world we observe around us, which exhibits all these attributes, is also, to some extent, bad. It would just be silly to think you could learn any important truths from experimenting on it. It's just *matter* -- pure potentiality, almost the absence of being. It's not very important.

Pretty much everyone in the West thinks this way until midway through the Renaissance, including Avicenna. I don't know about the Chinese, but I wouldn't be surprised if something similar is going on there.

Posted by: shoshana on November 12, 2007 at 12:40 AM | PERMALINK

santamonicamr, can I buy some of that glue? I need it to glue my tiger rock back together.

Posted by: Homer on November 12, 2007 at 12:56 AM | PERMALINK

Hindsight is 20-20. 'Tisn't really all that simple to describe rocks falling. How do you measure the speed experimentally? Since the rock is accelerating on the way down, the speed constantly changes. Most ancients (and moderns) would probably measure the distance of descent and divide this by the time of fall, which only gives average speed. Perhaps your next step would be to invent calculus and determine the relationships between time, distance, velocity, and acceleration.

Posted by: Luther on November 12, 2007 at 1:32 AM | PERMALINK

Re "why didn't the Chinese test it" question: just because Aristotle and the Western world got this wrong, we shouldn't assume the Chinese also didn't know the real scoop. Any historians of Chinese science out there?

Posted by: Brian Schmidt on November 12, 2007 at 2:33 AM | PERMALINK

Oh, ferchrissakes. The ONE TIME IN THE HISTORY OF THE INTERNET that someone types the words "any historians of science out there?" and I'm late to the party.

JS (@ 6:42 etc.) has it right, of course.

One persnickety-but-important thing to take away from all this: the "scientific method" we have today (actually any number of them, but never mind) is neither the first, last, or only acceptable/correct/useful method by which people learn about the natural world.

We're living at the apex of scientific thought in all of history because we perpetually redefine what "scientific" means. (For instance, whether an experiment--"butt simple" or otherwise--will tell you anything validly generalizable to the whole universe.) It's tempting, and flattering, to assume that we know better than Aristotle (and any other sufficiently elder figure) in some absolute sense. From the long view, it's closer to the truth to say that we are better than Aristotle at answering the questions that interest us. What those questions are, and what we accept as a legitimate answer, is strongly influenced by our broader culture--and it always has been.

The music of the 17th century is inadequate for me, although I can respect the work that went into it, and maybe make some condescending statements about what Bach could have done with a mixing board and saxophones. And I suppose it must have been insufficient for the people in the 17th century, too, because they kept changing it, little by little, until they were making music in very different ways and getting very different results. Still, I'd be a right pompous-sounding twit if I said they "didn't know how to do music" or "weren't doing it right" before the Doobie Brothers came on the scene. Ultimately, it's not all that different with science.

Posted by: Matt on November 12, 2007 at 4:00 AM | PERMALINK

Something I learned recently, about the origins of writing in ancient Sumeria...

It started out as accounting. People used little tokens - circles, cones, etc. - to keep track of sheep, measures of grain, etc.

After a while, they started sealing the tokens in clay envelopes as a means of keeping the transactions together.

But you couldn't get at the tokens without breaking the envelopes. So they made marks on the outside of the envelope to indicate how many tokens were inside.

Eventually, some bright boy figured out that once you made marks on the clay, you didn't need the tokens any more.

Nice, eh?

Now for the timeline:

People used the token system for more than FOUR THOUSAND YEARS before they made the leap. Think about that. Four thousand years....

Posted by: JeremyPDX on November 12, 2007 at 5:00 AM | PERMALINK

JS says, way upthread,

Aristotle was talking about motion through dense media, and said so. He said that the speed of fall through a medium is proportional to an object's mass as well as inversely proportional to the density of the medium.

But if this is so, isn't that claim clearly refuted by anything like the mythical Galileo experiment of dropping two balls of very different weights from a tower? If one ball weighs five times as much as the the other, and the medium is obviously of the same density in both cases, isn't anything like equal speed an absolutely decisive refutation of this claim? Shouldn't the heavier ball drop five times as fast, according to Aristotle's formula?

Of what matter is it that this all comes up in the context of Aristotle's discussion of a vacuum? Doesn't Kevin's original question recur, namely, why didn't all those smart people over about two millenia not see that a simple experiment refuted Aristotle's claim?

Posted by: frankly0 on November 12, 2007 at 8:30 AM | PERMALINK

The assumed they already had the answer, and people rarely bother asking questions they believe they already know the answer of.

Posted by: Soullite on November 12, 2007 at 9:16 AM | PERMALINK

Why didn't people drop rocks to see if they land at the same time?

Hmmm... lack of stopwatches maybe.

Posted by: DBake on November 12, 2007 at 10:21 AM | PERMALINK

What contemporaries really thought of Newton:

Nature and nature's laws lay hid in the night. God said, Let Newton be! and all was light!

Newton was actually regarded as a kind of superstar, back in the day . . .

Posted by: rea on November 12, 2007 at 11:05 AM | PERMALINK

"Hmmm... lack of stopwatches maybe."

This is close to the right answer. What G did was "dilute" falling motion by rolling balls down a plane. The question then is how did he time them. For many years the best theory was that he used his pulse. Later, the important fact was noticed that he was trained as s musician (his father more invented the idea of opera) a Lute player in fact. As you might know the Lute, unlike the Guitar has no frets, or rather movable frets made from sinew. What G did was to tie movable frets into the plane he was rolling balls down and move them back and forth until the slight click of the ball going over the fret happened. He moved them back and forth until the clicks came at regular intervals. A good musician can keep a beat to 1/100ths of a second. He then measured the distances from where the ball started and got the famous squared relationship. Science is essentially quantitative, that was really the important revolution.
Done.

Posted by: Webley Webster on November 12, 2007 at 11:10 AM | PERMALINK

Phalamir: "Actually going out and hurling rocks around the landscape would be belaboring the obvious..."

Not only that, it would *be labor.* As Crissa pointed out, the Greeks lived in a slave society. Labor was not a proper activity for those who think deep thoughts. Carl Sagan, among others, believed this is why the Greeks came so close to sparking a scientific revolution but ultimately failed.

As for aquatic intelligences, one thing's for sure: their understanding of thermodynamics would be crippled by an inability to experiment with flame. But if we're talking about dolphins, they would definitely have the edge in understanding anatomy, being equipped with built-in ultrasound scanners.

Bruce Moomaw: "at the very end of Apollo 15's three 7-hour moonwalks... James Irwin held up a big feather in one hand and a rock hammer in the other and dropped them at the same time..."

Most accounts say Apollo 15 commander Dave Scott did the Galileo experiment, not LMP Jim Irwin. Is that an urban legend, or is the mistake yours?

Posted by: Grumpy on November 12, 2007 at 11:13 AM | PERMALINK

Hmmm... lack of stopwatches maybe.

According to Aristotle's formula, a ball five times as heavy as another ball should fall five times as fast through the same medium (air).

Who needs a stopwatch?

Posted by: frankly0 on November 12, 2007 at 11:19 AM | PERMALINK

"According to Aristotle's formula, a ball five times as heavy as another ball should fall five times as fast through the same medium (air).

Who needs a stopwatch?"

Point taken. Refuting Aristotle should have been easier.

Figuring out that objects fall at the same speed though, would have been pretty hard without good instruments.

Btw, thanks for the info Webley.

Posted by: DBake on November 12, 2007 at 11:42 AM | PERMALINK

A lot of things seem so clear once they're explained clearly. As Thomas Huxley said after reading Darwin's On the Origin of Species: "How stupid of me not to have thought of that."

Posted by: QrazyQat on November 12, 2007 at 1:10 PM | PERMALINK

Regarding proportionality: (a) Actually, in his text Aristotle mentions proportionality only with respect to the density of the medium (air or water) -- for the mass he simply says that heavier objects will fall faster; however, it is often reported that he claimed proportionality for masses as well (I haven't found this in his text, though I did mention it earlier, which I shouldn't have done). (b) Since A's main discussion contrasts objects falling through different media, and he specifically mentions air and water, it is reasonable to assume that he was talking about terminal velocity -- which is proportional to the square root of the mass of the falling object, and inversely proportional to the square root of the drag coefficient, which depends partly on the density of the medium. That would be close enough.

Without question, A did not come up with exact formulas and if you hold him to the word "proportional" even for medium density he was strictly wrong; but if you look at whether the speeds of different bodies through a dense medium are equal or unequal, he was right -- even more so when terminal velocity has been reached.

Posted by: JS on November 12, 2007 at 1:15 PM | PERMALINK

They assumed they already had the answer, and people rarely bother asking questions they believe they already know the answer of. -Soullite

Years ago I saw this thinking process in action. I was giving a slide show in a small town about a 19th Century self-taught geologist who made significant fossil discoveries in our state that were very controversial. His theories about his discoveries challenged conventional wisdom at the time about evolution.

The sponsor of my lecture required audience participation, so I decided to give the audience a problem they could solve by asking me questions. (I wanted them to have the same discovery experience that the geologist had.) I held up an enlarged photo from 1913 of a man sitting at a desk in an office and asked, “Why does this man have two different kinds of phones on his desk?”

Through questions, the audience learned that the man worked for a utility company. One of the men in the audience was a retired employee of a similar utility and he got it fixed in his mind that the two phones were used to communicate with workers out in the field. No matter how he worded the questions, I always said no. He was so convinced that his prior experience explained the situation that he wouldn’t give it up.


Posted by: emmarose on November 12, 2007 at 1:22 PM | PERMALINK

It should also be said that Aristotle was not the greatest physicist of his time. The Pre-Socratic philosophers are considered by many to have been better, though much of their writings has been lost -- probably because the monks that helped preserve Aristotle and Plato had an interest in making sure that Democritus and Epicurus (who were atheists) were forgotten.

Schrodinger (who anticipated Kevin in using his cat in his day job) wrote with great respect about Democritus and his atomic theory. He made the point that modern atomic theory (starting with Gassendi and Descartes) was proposed by people who had read Democritus and Epicurus, and therefore its origins are directly tied to them. (This ancient atomism specifically claimed that the physical world consists of combinations of a finite number of types of atoms -- a mindblowing insight). It was probably Aristotle's greatest error that he rejected the atomic thory of Democritus, which later revolutionized science. Schrodinger remarks on the importance of the type of thinking used by these early atomists, which could not have been based on experimentation, and on its direct value to modern science.

Posted by: JS on November 12, 2007 at 1:41 PM | PERMALINK

Regarding proportionality: (a) Actually, in his text Aristotle mentions proportionality only with respect to the density of the medium (air or water) -- for the mass he simply says that heavier objects will fall faster; however, it is often reported that he claimed proportionality for masses as well (I haven't found this in his text, though I did mention it earlier, which I shouldn't have done).

That's an interesting point. I wonder whether his later interpreters may have embellished Aristotle's assertions to include proportionality based on mass. (Of course, the question would then arise as to why they might ever have believed this.)

In general, it's a little hard to take Aristotle to task for claims about this in any case. The man wrote a bazillion books on all kinds of subjects. Most thinkers might have invented, say, logic and called it a day. The exact speed of an object while falling could hardly be high on the list of things to which he would be devoting a lot of attention.

Posted by: frankly0 on November 12, 2007 at 1:42 PM | PERMALINK

I agree with Bleh, it revolves around the scientific method. People who were educated and wrote and published books were not interested in the scientific method. Either because it hadn't occurred to them, or because society held it in lower esteem than a more philosophical approach to problems.

If we consider that the few who could read and publish back then were equivalent to the current academic community, we'll see the current system comes with its own set of prejudices and requirements to be given attention by university presses and snobby academic readers. The quality of the research is not necessarily of the highest importance.

In English literature, my impression is that a very stylized writing --- often beautiful and obscure --- that demonstrates huge familiarity with contemporary criticism and places the writer inside of some particular literary criticism tradition, is the most important requirement, with the quality of literary analysis of little importance.

Posted by: catherineD on November 12, 2007 at 1:45 PM | PERMALINK

Just read Lucy's first comment and think she got it exactly right --- there is a huge resistance to change and many hoops to jump through, including required doctorate, etc., to even present your data, however well done your study.

Sounds like you've been having the same trouble I have....

Posted by: catherineD on November 12, 2007 at 2:09 PM | PERMALINK

OK -- looked again -- there is in fact a proportionality claim for masses as well in A. Again, this is claimed specifically for dense media. It is not far from the truth if considering terminal velocities. Heavy objects (like stones) are nowhere near terminal velocity when dropped from a building, but experiments in water (or honey) would show something close to that.

There are many more fascinating aspects to this. For example: Despite his experimental fame, Galileo made the explicit claim that he could prove Aristotle wrong only with a thought experiment -- no real experimentation needed, according to Salviati. His argument (that a heavy object attached to a light object would be slowed down by the light object in Aristotle's world) is specious, since the final velocity through a medium would depend on final weight AND volume AND shape. Galileo has been criticized for this analysis. This whole thing is very complex because of the role of dense media, terminal velocities, etc. But clearly, the common descriptions of A's thories as meant to apply to a vacuum are incorrect.

Posted by: JS on November 12, 2007 at 2:45 PM | PERMALINK

It is not far from the truth if considering terminal velocities.

Do you have any reason to believe that Aristotle really intended this analysis only for terminal velocities in dense media?

Not sure I get the logic of that claim. I realize that it makes his assertion of proportionality to mass less off the mark, but that's hardly an argument unto itself, I'd think.

Posted by: frankly0 on November 12, 2007 at 2:54 PM | PERMALINK

I live this blog! First the writing styles of lefties and righties and the implications for brain wiring, now this. Oh, and the occasional political post. Congratulations, Kevin, and especially to you commenters, for such enlightening fare.

Posted by: Longtime Listener on November 12, 2007 at 3:15 PM | PERMALINK

Uh, I *love* the blog ... although some days it does indeed seem that I live it.

Posted by: Longtime Listener on November 12, 2007 at 3:16 PM | PERMALINK

"We've only learned in recent years, thanks to the discovery of an Archimedes text hidden under medieval prayers, that he had pretty much worked out the foundation of calculus. "

Let's not get carried away here. The foundations of calculus are rooted in the real numbers, which the Greeks totally did not have. Not only did they not have them, they had such a retarded way of dealing with the rationals that it's not clear they would ever have gotten around to the concept of the reals.
I mean, these are the guys who apparently couldn't understand the simple concept of limits and how an infinite sum of small things could add up to a finite entity --- cf all those Zeno's "paradoxes" whose only paradoxical aspect is that anyone could get so confused about things that are so obvious.

Archimedes worked out some aspects of calculus, which is a very different thing from working out the foundations of calculus.

Posted by: Maynard Handley on November 12, 2007 at 3:51 PM | PERMALINK

"According to this article, “the fact of the uniqueness of free fall is even more remarkable in the light of modern physics, because it requires that two fundamentally different quantities, inertia and passive gravitational mass, always be exactly proportional to one another.”"

This is the sort of bullshit statement that gives popular physics a bad name.
What exactly is remarkable here? There is this theory, you know, called General Relativity, that is almost 100 years old that explicitly explains why this supposed distinction between "inertial" mass and "gravitational" mass is nonsense.

What's next? A discussion of how refrigerators are quite remarkable in light of the way that they seem to manufacture endless quantities of caloric?

Posted by: Maynard Handley on November 12, 2007 at 4:05 PM | PERMALINK

"Let's not get carried away here..."

yeah! and I can't believe Einstein didn't figure out that the universe initially expanded faster than the speed of light!

Posted by: Circe on November 12, 2007 at 4:08 PM | PERMALINK

Do you have any reason to believe that Aristotle really intended this analysis only for terminal velocities in dense media?

That he was talking about dense media is the main point here (read me earlier posts). In fact, his main objective was to prove that this is all that exists -- vacuum is impossible (he was wrong about this).

And since he talked about things moving through air vs. water, he was probably talking about terminal velocities -- through water, at least. Or -- he was observing terminal velocities in water or other liquids without realizing the difference between accelerated fall and terminal velocity.

Posted by: JS on November 12, 2007 at 4:11 PM | PERMALINK

"Did you actually drop a big rock and smaller rock over a cliff and observe that they both hit the ground 'at about the same time'? No; you reasoned backward from Newtonian physics and an elementary knowledge of air resistance in order to determine what would happen."

Oh come on. Drop a cup of water, something we have all done at some point, and it's obvious the two hit the ground at the same time. Metal cup, and we're talking a factor of 5 to 10 or so difference in the density of the objects.
(Let's assume Aristotle meant density rather than weight, because, as has already been pointed out, in terms of weight the statement is clearly stupid, on the grounds on pure logic, without even needing an empirical test.)

Or drop a single sheet of paper, and then a book. Now what's going on?

Bottom line is that Aristotle was, as far as I can tell, not in the slightest interested in any sort of coherent theory -- his theory was something like "an item will fall at the natural speed at which it falls". This sort of thing appears to go down well in the theological world, but it doesn't impress me much.

Posted by: Maynard Handley on November 12, 2007 at 4:11 PM | PERMALINK

"My gut tells me that matter is comprised of strings vibrating in 13 dimensions. There's no proof available; it's just a gut instinct. Call me silly."

And many people do (call you silly). See Peter Woit's blog.
This is precisely Kevin's point. Noawadays we don't just cheer Hallelujah when Leonard Susskind or one of his friends tells us that the world is composed of superstrings --- we demand some sort of proof.
There is plenty of proof for the current description of the world up to the Standard Model (apart from the lack of proof so far of the Higggs). There is ZERO proof so far for strings. Maybe it will come, maybe it won't, but either way, the issue will be argued over until it is resolved, not just accepted because someone said so.

Posted by: Maynard Handley on November 12, 2007 at 4:17 PM | PERMALINK

Archimedes worked out some aspects of calculus, which is a very different thing from working out the foundations of calculus.

From what little I know of Archimedes' quadrature, I'd say the problem wasn't that he didn't understand real numbers -- neither Newton nor Leibniz understood completeness, and unless you're willing to spot them Robinson's non-standard models the infinitesimals are right out too -- but that he didn't have a concept of a "general function", nor an understanding of the Fundamental Theorem.

Posted by: Anarch on November 12, 2007 at 4:24 PM | PERMALINK

I mean, these are the guys who apparently couldn't understand the simple concept of limits and how an infinite sum of small things could add up to a finite entity --- cf all those Zeno's "paradoxes"

Zeno and Archimedes were different people -- why assume that they had to be thinking alike just because they were both ancient Greeks?

Wikipedia says about Archimedes: "His early advances in calculus included the first known summation of an infinite series with a method that is still used today."

In the same commentary I mentioned earlier, Schrodinger (who knew a few things about calculus) explained why he believed that Democritus, also, had discovered the basic ideas of infinitesimal calculus -- and how adding an infinity of infinitesimal qauntites can result in a finite measure. Schrodinger believes that this is how Democritus developed the formula for the volume of a cone -- which he is known to have done.

Posted by: JS on November 12, 2007 at 4:25 PM | PERMALINK

"Still, I'd be a right pompous-sounding twit if I said they "didn't know how to do music" or "weren't doing it right" before the Doobie Brothers came on the scene. "

Why not?
Would you be happy with the statement that they didn't know how to do medicine?
Heck I'd be happy to make the statement that, right now, we don't know how to do psychiatry properly.

I don't understand the reluctance to people to point out that we're smarter than they were in the past. We are HUMANS not animals. We are more than just our genes and our bodies; we are our culture, our artifacts, and our accumulated knowledge. And all three of those are a damn sight more impressive than they were back in Aristotle's time.

And as for Bach's music. Well, the fact is that apart from a small minority, most people aren't much interested in listening to it. There are precious few teenagers who listen to it and think it expresses their inner emotional turmoil. There are precious few adults who listen to it and feel a burst of nostalgia.
I'd say we do music better nowadays, just like we do TV better than we did in the 1950s. People learn, and technology moves on.

Posted by: Maynard Handley on November 12, 2007 at 4:29 PM | PERMALINK

the standard model is sooo distracting...

that hammer that fell on my foot yesterday in the garage wuz nothing but a space-time warp? wtf? wow, that completely took my mind off that throbbing big toe...

Posted by: Circe on November 12, 2007 at 4:29 PM | PERMALINK

The trick with a lot of the great "discoveries" of early science over the centuries is that they really are probably not so much about the first person who bothered to do an experiment, but instead about the first person who realized that a certain observation was significant, emblematic, and who communicated it to contemporaries in a way that caused them to also realize that significance.

I have no doubt engineers and developers of technology (say for instance, catapults) have intuitively understood Newtonian mechanics since before even those clever Greeks. But it was a long time until there was a culture of academia in engineering and physics that would provide the framework for a clever individual to realize the significance of formalizing the experiment and observation that we now consider the foundation of our understanding of the world.

Posted by: Will Hutchinson on November 12, 2007 at 4:34 PM | PERMALINK

Since "absent observer" is probably absent right now, let me suggest that his post about about having an intuition about strings in 13 dimensions was rather obviously made in jest.

Posted by: JS on November 12, 2007 at 4:37 PM | PERMALINK

Circe: Just keep in mind that your big toe (or the particles that make it up) are also a form of space warp, and that will make it all better.

Grumpy: You may very well be right about Scott rather than Irwin dropping that feather and hammer on the Moon -- I was working off a 36-year-old memory. Whoever did it, it was a lot niftier than Shepard's golf match or the Apollo 11 astronauts' obviously pre-scripted exchange with Tacky Dick Nixon.

Posted by: Bruce Moomaw on November 12, 2007 at 4:38 PM | PERMALINK

I still find this very frustrating, can't figure it out:

who drops to their knees faster - the Dems to ok another gargantuan military spending bill or Bush, to look for that eight-ball that fell under the couch?

Posted by: Circe on November 12, 2007 at 4:52 PM | PERMALINK

Bruce, I have enough trouble accepting my big toe as it is... don't have to rub it in that it's warped...

Posted by: Circe on November 12, 2007 at 4:55 PM | PERMALINK

Aristotle's main success was probably not so much in the answers he gave, but in the questions he asked. Try to imagine what it must have been like for people to start thinking like this:

The question, what is place? presents many difficulties. An examination of all the relevant facts seems to lead to divergent conclusions.... Let us take for granted about it the various characteristics which are supposed correctly to belong to it essentially. We assume then- (1) Place is what contains that of which it is the place. (2) Place is no part of the thing. (3) The immediate place of a thing is neither less nor greater than the thing. (4) Place can be left behind by the thing and is separable...

Next for discussion after the subjects mentioned is Time. The best plan will be to begin by working out the difficulties connected with it, making use of the current arguments. First, does it belong to the class of things that exist or to that of things that do not exist? Then secondly, what is its nature?

It was in his investigation of what is "place" (or space) that A asks whether a void can exist, and it is in examining the latter question that he talks about falling bodies. For him, what was important was the investigation into the nature of space and time. And that is what is significant aboout his contributions too -- the questions he asked, and the way he asked them. That is easy to take for granted.

By the way, much of today's theoretical physics is proceeding without exprimentation -- because its claims cannot be tested (at this point in time, at any rate).

Posted by: JS on November 12, 2007 at 4:56 PM | PERMALINK

But, JS, what you have quoted is exactly why many of us have no patience with Aristotle. I mean, for christ sake, it is pure gobbledygook. What the hell does it mean, and what consequence flow from it?

It's not that I am impatient with philosophy, far from it. But I am interested in philosophy that actually answers meaningful questions. What the hell does the question "Is Time part of the things that exist or part of the things that don't exist" even mean? This is like arguing about whether or not the devil can take corporeal form, or whether the incredible Hulk could beat Harry Potter in a cooking competition, and equally as stupid and pointless.

Compare, say, Newton's viewpoint. Newton doesn't spout this meaningless crap. He says, OK, I'm going to treat space as a background co-ordinate system (I guess the equivalent of Aristotle's points (2) and (4)), with the mathematical structure of a 3-dimensional co-ordinate system with Euclidean geometry. Likewise for his mathematical model of time.

Now of course he got the precise mathematical details wrong. But at least he's using a language that allows for precision, and allows us to say things like "OK, I'm going to retain the idea of spacetime as a manifold, but instead of it having the form of a 3D space cross a 1D time with euclidean geometry, it's going to be 4D, with locally lorentzian geometry, and globally pseduo-Riemannian".

How do I make any sort of progress in Aristotle's world? I want to say "well, actually, Place is part of the thing", he says, no it isn't, and we're stuck at an impasse. Certainly we aren't going to get to Einstein's T=G description of how exactly "place is part of the thing" using Aristotelian language and concepts.

Posted by: Maynard Handley on November 12, 2007 at 5:20 PM | PERMALINK

MH, you seem to be saying that the concepts of space and time (as used by Newton in his formulas) are self-evident concepts that come naturally to the human mind. And that the only useful thing is to find quantitative relationships (a la Newton) that bind them to other physical quantities.

Others, however, believe that the development of these concepts as they eventually entered the world of physics was no mean feat by itself. And that, before Aristotle (and his contemporaries) came on the scene, many of these concepts were much less clearly articulated. (As a parallel, consider the appearance of the concept of number as separate from an actual collection of things. This is something that humans developed much earlier -- but it was a major breakthrough which we now take for granted).

And I'm sure I don't need to tell you that similar questions about the nature of space and time have occupied physicists much more recently than the Days of Aristotle and Newton. At a minimum, Aristotle realized that these were not easy concepts to define.

Posted by: JS on November 12, 2007 at 5:31 PM | PERMALINK

what's really pleasing about this thread is the abundance of positive quarks...

Posted by: Circe on November 12, 2007 at 5:52 PM | PERMALINK

No, JS, I am not saying that it is trivial to answer these questions. I am saying that meaningless answers don't deserve credit. Look I can play this game:
- time has mass (woo hoo, I'm a physicist)
- life is nothing but networks (woo hoo, now I'm a biologist)
- society is the result of man's Fear of the Outside, balanced against his Need for Others (note use of fancy Capitalization; now I'm a social scientist)

It's not enough to string some words together. It's not enough to simply *ask* questions. And amplifying on a single sentence description by giving an equally incompherensible book on the subject is not progress. My 500 page book on the vortex theory of how time has mass, into which I've thrown a dozen other insights as a bonus (it's madlibs time --- entropy is a category!, area is the same thing as information!, quark color obeys an uncertainty principle!) doesn't make any more sense than my extraction of its single best line.

To deserve credit, IMHO, you actually have to go some way towards providing a useful answer. I see nothing in Aristotle that enriches the world, or whose loss would have impeded the future development of physics.

Posted by: Maynard Handley on November 12, 2007 at 7:12 PM | PERMALINK

>What's the deal with the apparent failure to perform such a butt simple experiment over the course of 20 centuries?

Assumming it wasn't done: No need to try it; not even for curiousity sake. All experiments are done to get a result, for someone who wants an answer to a question; that logic, by itself, can't produce.

Posted by: James on November 12, 2007 at 7:14 PM | PERMALINK

Maynard--I actually would be unhappy with the statement that people back then (whenever) didn't know how to "do medicine". So would all the people who spent all their time doing it, in any of a hundred different ways. If you mean could they cure my staph infection, that's another thing.

There are two problems with grading the past against the yardstick of the now (e.g., declaring Us to be smarter than Them). First, you get the same uninteresting answer every time. If the purpose of history is to plot a bunch of dots to give us a vector so that we know our final destination (to hear you tell it, total knowledge-accumulated awesomeness; to hear others, utter moral decay and ruin) then count me out.

Second, and more importantly, when we say "yeah, but if X was so smart how come he didn't figure out Y," we learn nothing about X or Y but only about what we think is important, which we probably already knew. It's the same reason that historians don't write books with the thesis "Hitler was evil." You could fill fifteen thick volumes with meticulous evidence to that effect and when all was said and done, you'd have proved that people in 2007 tend to think that genocide, etc., are bad.

To my way of thinking, it's more interesting to ask "Given that genocide, etc., were widely regarded as evil in the 1930s and 40s, why did the German people support Hitler as long as they did?" That sort of question is kind of ruled out when you make up your own answer key with present-day definitions for what is good, bad, science, theology, correct, retarded, obvious, remarkable, impressive, an acceptable standard of proof, smart, impressive, better, meaningless crap, and progress--and then grade historical figures against it.

(P.S. Sorry for the Godwinning--hopefully the fact that I'm not saying anyone IS like Hitler makes it okay.)

Posted by: Matt on November 12, 2007 at 7:28 PM | PERMALINK

Got it, MH. Isn't this a wonderful world though -- you don't actually have to read Aristotle if you find him useless!

Posted by: JS on November 12, 2007 at 8:04 PM | PERMALINK

Although i could not read through all the comments, Bleh and his critic appear to have it correct. I have briefly studied the History of Science as it contributes to Economic Growth at the Master's level and the Scientific Revolution is generally thought to have occurred before the Enlightenment, and as such surely contributed to Enlightened ideologies. Cosmologies emphasizing the domination of man over nature, the rigor of mathematics, the power of the scientific method, and the notion that societies should advance over time so that younger generations continually live in better and better worlds become important. Advancement requires new technology and technology is comprised simply of knowledge. The components of Enlightenment ideologies mentioned above all contribute to increasing the stock of knowledge. However these worldviews are only fundamental when realized by changes in social structures. For example, China did indeed develop many of the technologies which were essential to European Industrialization, including gunpowder, the spinning jenny, the compass, advanced cartography, shipbuilding and weaponry, printing presses, and the use of coke instead of coal for smelting iron, which greatly increases the metals strength. However, this knowledge was not easily accessible due to limitations in the social structure. In other words, the marginal access costs (communication costs) were far too high so that useful, reliable, and scientific knowledge did not broadly or deeply permeate the masses. Ancient Chinese experts in metallurgy, textiles, porcelain, or any other trade almost certainly worked in a government controlled shop. Moreover, elite civil servants rarely were interested in or got involved with everyday worker mechanics and craftsmen. Rather they chose to pursue philosophic and supernatural questions. In short, there was no systematic investigation into understanding nature in China as their was in Europe. In Europe, especially the Dutch Netherlands and England, permeable social structures and an entrepreneurial class facilitated the exchange of knowledge between the tacit knowledge based doers (mechanics, artisans, craftsmen) and the explicit knowledge based theoretic thinkers (mathematicians, philosophers, etc.) The combination of tacit and explicit knowledge creates a synergy and this is the source of the rapid technological developments which propelled the West ahead of the East.

Posted by: Ben on November 12, 2007 at 8:36 PM | PERMALINK

The magic trick always seems easy once you've been shown how its done.

Posted by: The Fool on November 13, 2007 at 2:25 PM | PERMALINK




 

 

Read Jonathan Rowe remembrance and articles
Email Newsletter icon, E-mail Newsletter icon, Email List icon, E-mail List icon Sign up for Free News & Updates

Advertise in WM



buy from Amazon and
support the Monthly