Aristotle Killer of Science!

Recent times have seen a plague of Aristotle bashing basically accusing him of having held up the progress of science. I’m not sure if this started with Steven Weinberg’s book To Explain the World: The Discovery of Science but its publication and the interviews he gave, in which he forcibly expressed one or other version of this idea, certainly increased the occurrence of this accusation. Recently I stumble across a particular concise and trenchant version and I thought it might be instructive, as a historian of science, to analyse its core claim. As I hope to demonstrate only somebody totally ignorant of Western history could possible claim as, the splendidly named, Fuck Em Up Squanto (@Bro_Pair) did, on Twitter, that:

Aristotle was so smart it took world civilization 2000 years to recover from his disastrous physics ideas

First we need to get his time frame turned into concrete dates. According to Wikipedia, Aristotle lived from 384 to 322 BCE so following his death 2000 years would bring us to 1678 CE. Now most people who believe in a Scientific Revolution would date its commencement, and thus the overthrow of Aristotle’s stranglehold, somewhat earlier. Conventional wisdom dates its start to 1543 and the publication of Copernicus’ De Revolutionibus and Vesalius’ De fabrica. More recently David Wootton was touting the nova of 1572 as kick off point. Let us agree on a compromise date of 1600 CE so we have a claim that Aristotle singlehandedly prevented the invention or discovery (take you pick according to your personal philosophy of science) of physics from 322 BCE until 1600 CE.

The first problem is what exactly Fuck Em Up Squanto means by physics. For Aristotle physics was the study of nature and included much that we would now file under natural history but I assume our intrepid tweeter means something approximating to our modern definition of physics and I shall proceed on this assumption. Aristotle contributed thoughts to three major areas that could today be considered parts of physics, astronomy, optics and dynamics. We will briefly look at each of these and its acceptance in antiquity before marching forward through history to the seventeenth century.

In astronomy Aristotle took over and modified the homocentric theories of Eudoxus. Basically a geocentric model using nested spheres to try and reproduce the real movements of the planets and this was already superceded in antiquity, in the second century CE, by the epicycle and deferent models of Ptolemaeus, although much of Aristotle’s cosmology was, at least nominally, retained, of which more later. This means that any (as we will see, misplaced) blame for Greek astronomy should be addressed to Ptolemaeus and not Aristotle.

In optics we actually have a very interesting situation. Amongst the Greeks there are several competing models to explain sight of which one is Aristotle’s. What is interesting here is that Aristotle’s model is a so-called mediumistic one, that is a connection is built up between the eye and the seen object through the medium of the light and the air and the information that constitutes seeing is transmitted to the eye by vibration. This bears a strong resemblance to the wave theory of light developed by Hooke and Huygens in the seventeenth century. In fact some historians of optics go so far as to see Aristotle as a precursor of his seventeenth century colleges. I personally think this is a step too far but at least one cannot accuse Aristotle of stopping the development of modern physics in the field of optics, rather he was ahead of his times. Actually in the optics competition in antiquity Aristotle’s theory didn’t find many takers, the geometric intromission theories of Euclid, Heron and Ptolemy mostly making the running. Again, nothing to blame Aristotle with here.

It is of course in the field of dynamics, the theory of motion, that we will find to true cause of complaint because it is exactly here that Galileo, Newton et al made the great strides that people hail as the scientific revolution, Galileo’s laws of fall and Newton’s laws of motion. So let us examine Aristotle’s theories and their progress through the two thousand years that separate him from the good old Isaac.

Aristotle’s theories of motion seem rather strange when viewed from a modern standpoint. Firstly he regarded motion as just one form of change, change of place. Other forms of change were growth and decay for example. Considering change just for itself he thought it could be divided into natural motion and violent motion. Natural motion was fall on the earth and the motion of the celestial bodies. Celestial bodies moved naturally in circles, a theory he took over from Empedocles, as did most Greek philosophers. Aristotle’s homocentric astronomy of nested spheres functioned like a giant friction drive system with each sphere driving the sphere inside it. Only the outer most sphere needed a driver, Aristotle’s unmoved mover. On the earth, things dropped fell to the earth because they were returning to their natural place. Implying some sort of low-level animism.

All forms of violent, that is non-natural, motion require a mover, which is where Aristotle’s problems start. Why does something that is thrown continue to move once it has left the throwing hand? Aristotle came up with an explanation of the air opening up in front of the thrown object and closing behind it continue to push the object. He was never very happy with his own solution.

On fall modern commentators tend to mock Aristotle because he said heavy objects fall faster than light ones. Because of Galileo we know better! But we don’t. Galileo’s laws of fall are valid for objects falling in a vacuum. Aristotle’s claims are based on observation in the real world. In fact if you formalise Aristotle’s thoughts on fall, what comes out is very close to Stokes’ laws for fall in a viscous fluid. Air is a viscous fluid.

Aristotle’s theories of motion were not all dominant in antiquity but where just the views of one school of philosophy amongst several. In fact in later antiquity the physics of the Stoics was far more prevalent that that of Aristotle. Around the end of the second century CE Romano-Hellenistic society and culture went into decline and eventually total collapse and with it all forms of intellectual endeavour in Europe. Talk of 2000 years of Aristotelian blockage of science becomes simply ridiculous.

A revival of Greek knowledge began in the Islamic Empire in the eighth century CE. Aristotle’s works were known to the Islamic scholars and highly respected but one cannot speak of any form of total dominance or hindrance of the development of science. The Islamic Empire saw advances in mathematics, medicine, engineering, optics and astronomy.

Around one thousand CE Europe started to again develop an urban civilisation and a thirst for knowledge. In the eleventh and twelfth centuries the so-called translators brought translations into Latin of both the ancient Greek and the more recent Arabic knowledge. At first the Catholic Church, the main centre of learning, was wary of what they saw as heathen knowledge and it was first in the latter part of the thirteenth century that Albertus Magnus and Thomas Aquinas created an acceptable melange of Christian theology and Aristotelian philosophy. Particularly appealing was Aristotle’s unmoved mover whom the equated with the Christian God. It is this that people like Fuck Em Up Squanto are referencing with their objections to Aristotle. However we are now talking about the period thirteen hundred to sixteen hundred that is three hundred not two thousand years! But even here we have to be very careful of our criticism of Aristotle.

As Edward Grant, expert historian of medieval science and religion, quipped (medieval) Aristotelian philosophy was not Aristotle’s philosophy. That is the compromise that Albertus Magnus and Thomas Aquinas created between Christian theology and what the considered to be Aristotelian philosophy differed considerably from the philosophy that Aristotle presented in the fourth century BCE. Another point that Grant makes is that it’s very difficult to actually say what Aristotelian philosophy was as it changes constantly throughout the High Middle Ages. That Aristotelian Philosophy was some sort of unchanging, unchangeable monster cast in concrete by the Catholic Church with an injunction against all forms of inquiry is a myth perpetuated by people who believe in the Draper-White hypothesis of an eternal war between science and religion.

Let us look at a specific example of that process of change; in fact an area that would play a central role in the creation of modern science in the Early modern period, the laws of motion. Already in the sixth century CE John Philoponus criticised Aristotle theory of motion and introduced the concept of impetus. This stated that the thrower imparted a motive force to the thrown object, impetus, which decreases over time till the object stops moving. Via the Islamic thinker Nur ad-Din al-Bitruji in the twelfth century the theory was taken up and elaborated by Jean Buridan in the fourteenth century and through him entered mainstream Medieval thought. The theory of impetus played a central role in the early considerations of both Giambattista Benedetti and Galileo who developed the modern laws of fall. The seventeenth-century theory of inertia, Newton’s first law of motion is in reality a consequent development of the theory of impetus.

Also in the fourteenth century the so-called Oxford Calculatores developed mathematical quantified version of Aristotle’s theories, in particular deriving the mean speed theorem, which lies at the heart of the laws of fall. The Paris physicists took up this work and produced graphical representations of the mean speed theorem identical to the ones presented later by Galileo. To quote historian of mathematics, Clifford Truesdall:

The now published sources prove to us, beyond contention, that the main kinematical properties of uniform accelerated motion, still attributed to Galileo by the physics texts, were discovered and proved by scholars of Merton college…. In principle, the qualities of Greek physics were replaced, at least for motions, by the numerical quantities that have ruled Western science ever since. The work was quickly diffused into France, Italy, and other parts of Europe. Almost immediately, Giovanni di Casale and Nicole Oresme found how to represent the results by geometrical graphs, introducing the connection between geometry and the physical world that became a second characteristic habit of Western thought …

These are medieval scholars working within the Aristotelian tradition not blocking science but furthering it.

The optics that the scholastics inherited from the Islamic Empire was that of Ibn al-Haytham, introduced into Europe in the thirteenth century by Roger Bacon, John Peckham and Witelo, and not that of Aristotle. This European version of al-Haytham’s optics laid the basis on which Kepler and others developed modern optics in the seventeenth century. This optics formed a central part of the medieval university science curriculum, no obstruction from Aristotle here.

As already stated above the geocentric astronomy inherited by the medieval universities was that of Ptolemaeus and not Aristotle’s. On the whole during the period leading up to Copernicus whenever Ptolemaic astronomy clashed with Aristotelian cosmology, the astronomers had little problem abandoning Aristotle’s thought in favour of mathematical observation. The period between fourteen hundred and sixteenth hundred saw a steady modification and improvement in Ptolemaic astronomy. Copernicus’ work was part of a general programme of improvement and not some sort of rebellion against an unchanging or unchangeable orthodoxy. That Copernicus’ ideas were not accepted immediately lies in their inherent scientific problems and not some sort of rejection for being heterodox.

Although the above is fairly superficial I hope that I have made clear that the claim that Aristotle’s ideas were detrimental for the development of science for two thousand years in quite simply historical rubbish.










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34 responses to “Aristotle Killer of Science!

  1. If you wanted to go Draper/White on this issue, you could pretty easily put together a Warfare of Aristotle and Theology book. Aristotelian philosophers routinely fell afoul of church authorities, not merely because specific Aristotelian tenets contradicted dogma—the eternity of the world, the individual immortality of the soul, the ability of God to know particular things—but because Aristotle was all about the independent validity and value of wanting to know. The conservative strain in the church has repeatedly objected to that. It’s the fundamental rationale of Étienne Tempier 1277 condemnation of Aquinas. Too damn much interest in physics. Too great a commitment to reason. Too much Aristotle. For religious moralists, curiosity is a vice. For Aristotle, “All men naturally desire to know.”

    I haven’t made a study of it and would be the right person to do so in any case, but I suspect that even the reaction against Aristotle at the beginning of the Scientific Revolution had as much religious as scientific motivation. The Protestant Peter Ramus didn’t cut much of a figure as a physicist, but he was probably a more effective enemy of Aristotle than Galileo ever was, and Francis Bacon, another famous anti-Aristotelian, was a Puritan who associated Aristotle with the theological mumbo jumbo of the Papists. Meanwhile, the Catholics were making life very difficult for Renaissance academic Aristotelians. The instruments were shown to them rather more often than they were to that other Italian guy.

  2. João Neto

    In this url,, you can find a good argument about how Aristotle’s dynamics was a pretty good theory to describe our world of human experience.

    Thanks for all the great work you place in your blog,

  3. Recent times have seen a plague of Aristotle bashing basically accusing him of having held up the progress of science. I’m not sure if this started with Steven Weinberg’s book To Explain the World: The Discovery of Science …

    Nope, much older. For example, here are a few choice passages from Koestler’s The Sleepwalkers:

    From Plato and Aristotle onward, natural science begins to fall into disrepute and decay, and the achievements of the Greeks are only rediscovered a millennium and a half later.

    Plato had merely thrown out, in semi-allegorical language, a suggestion which was quite in keeping with the Pythagorean tradition; it was Aristotle who promoted the idea of circular motion to a dogma of astronomy.

    Aristotle closed the lid again with a bang, shoved the earth back into the world’s centre, and deprived it of motion.

    …Aristotle had a millennial stranglehold on physics and astronomy…

    We shall have occasion, later on, to marvel at the disastrous effects of this Aristotelian brainwave on the course of European science…

    Aristotle divorced science from mathematics.

    Aristotelian physics is really a pseudo-science, out of which not a single discovery, invention or new insight has come in two thousand years; nor could it ever come — and that was its second profound attraction.

    • Will Thomas

      For an amazing example of Aristotle as scientific heel, see Disney’s “Our Friend the Atom” (a TV special made to boost support for atomic power).

    • “Aristotelian physics is really a pseudo-science, out of which not a single discovery, invention or new insight has come in two thousand years; nor could it ever come”: Its worth saying that for at least 600 years, a good many people have owed their lives or fame to the fact that Aristotelian physics is a good practical working model for fencers. Its not perfect, but it gives a framework for analysing problems and proposing solutions, and it does not require mathematical formalisms which nobody can manipulate while someone is stabbing a lance at their face. Sydney Anglo, Ken Mondschein, Classical Fencing and La Verdadera Destreza are some good keywords for anyone interested to type into their favourite library catalogue.

  4. A small correction for you ” by the epicycle and different models of Ptolemaeus” should be “and deferent model”.

  5. ucronio spirolazzi

    I recommend this: C. Rovelli, Aristotle’s Physics: a Physicist’s Look

  6. Phillip Helbig

    It was probably not so much Aristotle himself but rather the penalties put on those who questioned authority which held up progress, especially after Aquinas essentially elevated Aristotle almost to religious levels.

    All the same, I don’t have too much respect for a dude who wrote that men and women have different numbers of teeth, even though he was married more than once. And this guy, in contrast to Plato, is supposed to be the champion of observation? OK, maybe his wives had a different number of teeth than he did, but still. Seems he should have done some more field work.

    • Walter Hehl


      in this blog below you will find a competent replique to your quote on the number of teeth of women and on Aristotle’s attitude regarding own observation:

      The author Robin Herbert cites also the original Aristotle:
      ”Males have more teeth than females in the case of men, sheep, goats, and swine; in the case of other animals observations have not yet been made.”
      This means that Aristotle regarded this as a confirmed observation, his fault of course. He was emphasizing the role and value of observation, but in the context of the knowledge of his time. As we do.

      • laura

        I see this complaint about the teeth everywhere. But Aristotle wrote *a lot of stuff*. Are there any other examples of him making a similar just-not-willing-to-look error (which could equally be applied to, say, Galen)? Or is this a one-off?

      • Laura, that is a very good point: actual historians of science tend to have a lot of respect for Aristotle’s statements about the bodies and behaviours of animals and sea creatures. Everyone makes mistakes, especially when they are giving lectures (and quite a few of the surviving “works of Aristotle” seem to be lecture notes). Indeed, most of the loudest abusers of Aristotle do not give me the impression that they have read any of his works, let alone any of the works of his later students.

    • “…the penalties put on those who questioned authority which held up progress…”

      Would you care to give a real example of this with relation to science in the scholastic/High Medieval period?

      • Phillip Helbig

        Why did Copernicus wait until he was almost dead, and then only after he was convinced, to publish? Many heretics, witches, etc were killed, and these were mostly people who believed in Christianity, though in a different form. Not believing at all was deadly. Of course, most people don’t want to die, so they kept quiet about it. I don’t have reference books near me, but certainly people were banned from teaching who didn’t toe the line. Wars were fought over details in doctrine. There was capital punishment for belonging to certain religions in some places. Openly belonging to none was out of the question.

        Are you saying that the status Aristotle obtained through Aquinas did not hinder progress at all?

      • Phillip, I wrote a blog post against the oft repeated claim that Aristotle somehow blocked the progress of science and I think explained that this was simply not true.

        You then in your comment made the very vague claim that [it was] “the penalties put on those who questioned authority which held up progress”. I asked your to give concrete examples with respect to science to justify this claim. Your answer consists of a lot of hand waving, some comments about things that have nothing to do with science and one suggestive question relative to the history of science to which the real answer does not in any way help your case.

        Historians of astronomy are now certain that Copernicus refrained from publishing because he couldn’t deliver and not because of any religious fear or pressure. In fact the only pressure he received from the side of the Church was leading Church figures urging him to publish. One of them even offered to cover the cost of producing a publishable manuscript.

        Copernicus didn’t publish because in the Commentariolus he had promised to prove the truth of the heliocentric hypothesis and despite all the effort that he had invested in De revolutionibus he was a long way away from achieving that goal.

        Burning people for heresy or witchcraft are purely Christian affairs and to attempt to attribute blame to Aristotle for those things would be funny if the subject was not such a serious one. By the way most of the witch burning took place during the Early Modern Period after Aristotle had ceased to influence intellectual discourse. It was also just as widespread amongst Protestants as it was amongst Catholics.

        So all in all I’m still waiting for you to provide concrete examples to justify your statement relative to the progress of science.

  7. Thony writes:

    In fact if you formalise Aristotle’s thoughts on fall, what comes out is very close to Stokes’ laws for fall in a viscous fluid. Air is a viscous fluid.

    Technically this is true, but in this context, the viscosity of air is negligible. Something like oil gives you the Stokes regime; the (dynamic) viscosity of oil is thousands of times the viscosity of air (around 4000 for olive oil, one of the less viscid ones, at 25 degrees C).

    The relevant fluid forces here are the ones Rovelli uses (in the article cited by Spirolazzi): drag force (proportional to v squared, unlike viscous friction, which is proportional to v), and buoyant force.

    • Walter Hehl

      If the sphere is small enough, the fall (sedimentation) is easy-to-understand, even analytically, since 1851. An example with oil-in-air is the famous Millikan-Experiment with oil droplets steadily falling in air. In any case, if you let fall a sphere in a medium, there is a built-up phase and an asymptotic terminal velocity. In any case
      • the terminal velocity is the higher the densier the material of the sphere,
      • the initial acceleration is the higher the densier the material,
      • if the viscosity resp. air resistance were 0 (vacuum), the terminal velocity were infinite.
      All these statements are correct – and Aristotelian. What is missing, is the effect that gravity is not constant (it increases when approaching the earth down to a couple of kilometers under the surface, and then diminishes to zero at the earth’s center. But this Aristotle really could not know!

      • All points Rovelli makes.

        I think it goes a little too far though to call these Aristotelian statements (nor does Rovelli put it that way). After all, neither terminal velocity nor acceleration are really Aristotelian concepts. Rather, we can (anachronistically) “save” Aristotle by invoking modern physics in the right way.

        Since the condemnation of Aristotle is just as anachronistic, this serves as a useful corrective.

    • I should have said something like “inertial drag” rather than just “drag”. A good discussion of the difference between inertial and viscous drag can be found on this page by Michael Fowler.

  8. Gules

    I can’t claim to know much about Aristotle, but I have noticed a change in the philosophy of science that at least in some regards means a return to aristotelian (pre-Galilei/Newton/Hume) concepts.

    Harré & Madden (Causal Powers: Theory of Natural Necessity, 1975), Roy Bhaskar (A Realist Theory of Science, 1975) Nancy Cartwright (How the Laws of Physics Lie, 1983), David Armstrong (What is a Law of Nature?, 1983), Bigelow, Ellis & Lierse (Natural Necessity and Laws of Nature, 1992), John Heil (The Nature of True Minds, 1992), Stephen Mumford (Dispositions, 1994) Brian Ellis (Scientific Essentialism, 2001), George Molnar (Powers: A Study in Metaphysics, 2003 ), Alexander Bird (Nature’s Metaphysics: Laws and Properties, 2007), Anjan Chakravartty (A Metaphysics for Scientific Realism: Knowing the Unobservable, 2007) etc.

    They all formulate somewhat different theories but they all reject humean-empiricist concepts of causality and proposes that “natural laws” should be understood as forces/dispositions inherent to the objects themselves. It is a shift of focus back to what Galilei rejected as “occult qualities”.

    • dsthorne

      To that list, add Edward Feser’s _Scholastic Metaphysics_, which firmly champions hylemorphism as necessarily foundational to modern physics.

      • Jeb

        “Another point that Grant makes is that it’s very difficult to actually say what Aristotelian philosophy was as it changes constantly throughout the High Middle Ages.”

        You could deploy the same argument to suggest that the retro term ‘Romano-Hellenistic’ is ahistorical. i.e tastes and values of Rome were fluid and could not provide a stable pattern for emulation.

        I don’t think the argument works in regard to making the choice in a specific historical context to become more like a Roman.

        May be a tendency to deny agency and motivation to individuals in these forms of argument.

  9. C M Graney

    I find Buridan’s work quite interesting. Some want to say it is not the same as the modern idea of momentum (S. Weinberg is an example), Buridan sure describes it and quantifies it in a way consistent with momentum. But not everyone followed Buridan closely. For example, Tycho Brahe talks of impetus as a sort of thing that sort of naturally runs out of gas (as I recall, so did Philoponus). Buridan, by contrast, thinks impetus lasts forever if no resistance corrupts it. At any rate, impetus shows that Aristotle did not just own the road for 2000 years in physics.

    For Buridan on Impetus:

    Analysis of Buridan on Impetus by yours truly: or

    • Sorry Chris, your comment got stuck in the spam filter for a couple of days from whence I have just liberated it.

    • The discussion on the exact scientific implications of Buridan’s version of the impetus theory is indeed an interesting one, but one to which I don’t think there will ever be a definitive answer. However, what is certain is the the impetus theory was an important and highly influential step on the way to the theory of inertia

  10. Pingback: Whewell’s Gazette: Year 2, Vol. #22 | Whewell's Ghost

  11. wmconnolley

    You must be aware of (the thing, not necessarily the wiki article :-). I’ve only just run across it) and it seems a bit odd not to mention it. I think it’s what JH is referring to with “It’s the fundamental rationale of Étienne Tempier 1277 condemnation of Aquinas” but that’s a somewhat odd way of referring to it, since it was a condemnation of Aristotle. To quote from the article “Pierre Duhem and Edward Grant state this caused a break from Aristotle’s work and forced the teachers of the time to believe Aristotle’s work imperfect. According to Duhem, “if we must assign a date for the birth of modern science, we would, without doubt, choose the year 1277”.

  12. Sylvan

    There was nothing wrong with Aristotle’s curiosity or claims, the issue was the cult that surrounded his ideas that stifled future inquiry. There wasn’t a spirit of test all the things, it was more like ‘Okay we know this, so we can move on”. Not his fault for being a genius with limited tools, but it was the fault of scholars for centuries that they didn’t make their own inquiries into the nature of the world.

    • What you are claiming is a standard myth, which I go to some lengths to dismantle in my post if only you read it carefully enough. From its return in the thirteenth century up to its final demise at the end of the seventeenth, Aristotle’s philosophy was continually subjected to scrutiny and changed and modified by the scholars studying and using it.

  13. Caryl

    I have not read Aristotle’s works, but what about
    his opposition of Democritus, or his observations on fish spontaneously arising from mud?…
    I have read over the years and feel that his thoughts and his influence slowed acceptance of true understanding in those areas.
    I am asking for genuine input- not putdowns.

  14. Sorry to have taken so long to answer your query.

    Firstly, his position to the Atomists was based on a careful logical analysis and a strong philosophical argument. In fact almost all we know about the original Atomists is taken from Aristotle’s presentation of their beliefs. Secondly, it is a major mistake to think that, apart from the use of the word atom, ancient Greek atomism has anything in common with modern atomic theory, it doesn’t.

    As for patently false statements in Aristotle’s work, show me any scientist or philosopher, who hasn’t made some. Yes, he got a lot wrong but so did Kepler, Descartes, Newton and Einstein just to mention a few.

    What, however, Aristotle did was to make major contributions to logic in general and scientific methodology in particular.

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