“Thus Aristotle laid it down that a heavy object falls faster than a light one does. The important thing about this idea is not that he was wrong, but that it never occurred to Aristotle to check it.”
Albert Szent-Györgyi de Nagyrápolt, winner of the Nobel Prize in Physiology or Medicine.
A good point—but also note that, when Galileo argued against Artistotelian physics in his Dialogue Concerning the Two Chief World Systems, he set forth instead the idea of the inertial reference frame—but Galileo also never felt the need to perform an experiment to verify that his shipboard “experiments” would work as he predicted. Both the wrong conclusion, and the right conclusion, were arrived at via thought-experiment. And when Einstein took the next step by proposing the special theory of relativity, that too was a thought-experiment with no validation.
In fact, one can go further, because Aristotle’s conclusion was presumably arrived at in the first place through observation of everyday experience (indeed, it almost seems wrong to attribute it specifically to Aristotle since it is simply the “common sense” view of most of humanity, before and since). So here we arguably have an example of a thought experiment successfully refuting an empirically-derived hypothesis.
I checked Aristotle’s ‘On the Heavens’ and ‘Physics’. Nowhere could I find him saying that a heavy object falls faster than a light one. Aren’t it the Aristotelian scholars who said that and who are to blame? Aristotle distinguished relative weight (our mass) and absolute weight (our mass density) and gives practical examples to check that denser objects move faster downwards in water than less dense objects, if the objects have the same shape.
It’s also worth noting that when you do Galileo’s Tower of Pisa experiment, the heavier object does land first. (You think you release them at the same time, but you don’t—your muscles let the heavier object go first.)
I find sometimes we here denigrate our distant predecessors too much; I have heard well-educated people call the Greeks fools for rejecting heliocentrism, despite the fact that the Greeks had powerful arguments against heliocentrism like the lack of stellar parallax, or we mock them for the 5 elements, despite the incredible feat of devising atomism just by considering basic logical paradoxes caused by alternative ontologies.
For any two portions of fire, small or great, will exhibit the same ratio of solid to void, but the upward movement of the greater is quicker than that of the less, just as the downward movement of a mass of gold or lead, or of any other body endowed with weight, is quicker in proportion to its size.
Note that he take the extreme position that heavier objects fall faster, not just denser! This claim is robust against translation errors since he is keeping the material fixed. I have not been able to find the passage you mention, though I did find a discussion of objects falling slower in water than air.
“Thus Aristotle laid it down that a heavy object falls faster than a light one does. The important thing about this idea is not that he was wrong, but that it never occurred to Aristotle to check it.” Albert Szent-Györgyi de Nagyrápolt, winner of the Nobel Prize in Physiology or Medicine.
A good point—but also note that, when Galileo argued against Artistotelian physics in his Dialogue Concerning the Two Chief World Systems, he set forth instead the idea of the inertial reference frame—but Galileo also never felt the need to perform an experiment to verify that his shipboard “experiments” would work as he predicted. Both the wrong conclusion, and the right conclusion, were arrived at via thought-experiment. And when Einstein took the next step by proposing the special theory of relativity, that too was a thought-experiment with no validation.
In fact, one can go further, because Aristotle’s conclusion was presumably arrived at in the first place through observation of everyday experience (indeed, it almost seems wrong to attribute it specifically to Aristotle since it is simply the “common sense” view of most of humanity, before and since). So here we arguably have an example of a thought experiment successfully refuting an empirically-derived hypothesis.
I checked Aristotle’s ‘On the Heavens’ and ‘Physics’. Nowhere could I find him saying that a heavy object falls faster than a light one. Aren’t it the Aristotelian scholars who said that and who are to blame? Aristotle distinguished relative weight (our mass) and absolute weight (our mass density) and gives practical examples to check that denser objects move faster downwards in water than less dense objects, if the objects have the same shape.
It’s also worth noting that when you do Galileo’s Tower of Pisa experiment, the heavier object does land first. (You think you release them at the same time, but you don’t—your muscles let the heavier object go first.)
I find sometimes we here denigrate our distant predecessors too much; I have heard well-educated people call the Greeks fools for rejecting heliocentrism, despite the fact that the Greeks had powerful arguments against heliocentrism like the lack of stellar parallax, or we mock them for the 5 elements, despite the incredible feat of devising atomism just by considering basic logical paradoxes caused by alternative ontologies.
And even if you do, there is air to consider.
Aristotle really said it, in Heavens 4.2:
Note that he take the extreme position that heavier objects fall faster, not just denser! This claim is robust against translation errors since he is keeping the material fixed. I have not been able to find the passage you mention, though I did find a discussion of objects falling slower in water than air.
Just out of curiosity: do you know the origin of that quote? I’ve tried to find the citation before, but been unable.