43 - Classified Information: Aristotle's Biology

Posted on 24 July 2011

Aristotle’s scientific outlook is perhaps best displayed in his zoology. Peter looks at his theories of inheritance, spontaneous generation, and the eternity of animal species.

Further Reading

• S. Connell, Aristotle on Female Animals (Cambridge: 2016).

• D. Devereux and P. Pellegrin (eds), Biologie, logique et métaphysique chez Aristote (Paris: 1990).

• D. Ebrey, Theory and Practice in Aristotle’s Natural Science (Cambridge: 2015).

• A. Gotthelf and J.G. Lennox (eds), Philosophical Issues in Aristotle’s Biology (Cambridge: 1987).

• D. Henry, “Aristotle on the Mechanism of Inheritance,” Journal of the History of Biology 39 (2006), 425–455.

• J.G. Lennox, Aristotle’s Philosophy of Biology (Cambridge: 2001).

• G.E.R. Lloyd, Aristotelian Explorations (Cambridge: 1996).

Devin Henry’s website with several papers on Aristotle’s biology:

Stanford Encyclopedia: Aristotle's Biology


Peter Adamson 23 July 2011

Please note that this is the last episode that will appear until early September -- I am taking a short break in August!

I'd also like here to thank Devin Henry for his help with this episode. Check out his website, listed here in "further reading"!

Louis R. 16 March 2012

I just listened to the episode pertaining to Aristotle on 'Form and Function' and it appeared to me you were implying that Darwin debunked Aristotle with his theory of Evolution. As I am aware there still remains a debate on the subject matter, (see secular Scientist/Mathematicians David Berlinski's 'The Devil's Delusion'), not to say that life does not evolve through natural selection, but to question it's limitations and/or true potential. That's a side issue really, however it is the core of the theory which I find puzzling, that it's merely a "blind process" of chance with no causal agent. Is that not a philosophical claim rather than a scientific claim? How does science prove this to be a true statement empirically? How does knowing the mechanism of a thing debunk the existence of a causal agent, or tell of it having or not having an end purpose? It doesn't seem, to me at least and I could be mistaken, that Darwin's interpretation of the data is empirical fact and therefore successfully debunks Aristotle's philosophy.

Thanks very much Louis, this is an interesting issue. What I'd say is that Aristotle denies explicitly that chance could give rise to a natural world that is dominated by regularity, in particular in the case of animals; and that Darwin's theory shows us how chance could do just that. So the thought would be that Aristotle says "here is a phenomenon that could only be explained through non-random causation" and Darwin says "well, here's a way that random causation could give you the same result" -- that counts as a refutation even without doing any empirical research, in the same way that someone might say "there's no way to travel to Jupiter" and then be refuted with an explanation of how it could be done (even without going to Jupiter).

Something else to consider here, though, is whether Aristotle could win the war despite losing the battle. Even if he is wrong about chance, he might be right that natural scientists need to invoke final causation in accounting for animals and other organisms, for instance by saying that the "purpose" of a giraffe's neck is to reach leaves. And one could, as you I think are suggesting, still insist that such purposive language is appropriate even if its presence were explained by a Darwinian genetic account. (Imagine trying to do biology without ever using teleological/purposive language -- would not be easy!) A lot turns here on the question of how robust Aristotle's appeal to final causes is supposed to be -- is he just saying that they need to enter into our explanations or that they are actual items in our ontology, as it were?

Louis R. 16 March 2012

In reply to by Peter Adamson

"is he just saying that they need to enter into our explanations or that they are actual items in our ontology, as it were?"

That is a great question, I'm only now researching Aristotle so forgive me of my ignorance, I would assume he believes purpose is ontological, correct?

Actually the question is one that is hotly disputed in the secondary literature. Some think that the appeal to final causes is "merely explanatory" or "heuristic" -- we need to think of things in terms of purposes but one could also give complete metaphysical account (i.e. give sufficient conditions) by appealing only to formal, material and efficient causes. Some want to say no, the metaphysical causal picture would then be incomplete, and I lean towards that direction but it's a difficult issue.

Peter Lührs 7 June 2012

In reply to by Peter Adamson

Hello Peter,

first I'd like to say that I've been listening with great interest and pleasure to your series on Aristotle so far, being a student of biology and having a deep interest in Aristotle from that point of view as well as in the broader philosophical perspective.

I have to disagree with you though on the assessment that Darwin's theory of Evolution shows a way how a chance process produces regularity in nature. Actually, the regularity isn't at all explained by the chance process in the theory of evolution in my opinion: The explanatory work that is done in that regard within the Darwinian theory is done by the mechanism of natural selection. And that mechanism is quite the non-random mechanism, as those variations are selected that fit the environment.

In my opinion Aristotle is onto something with his assertion. He is justified to reply to Darwin "but you don't explain the regularity with a random process here." And he could go on about how natural selection is (?) merely a way to say that there needs to be a "purposive" relation between an animal (or any other living being/it's parts) and it's environment, no?

I don't think that one can so easily dismiss Aristotle with appeal to Darwinian evolution.

Peter L.

Hello Peter,

Thanks for your message and let me congratulate you on your admirable first name. But seriously: I think I agree with you here, at least to some extent. Part of what I wanted to say on the episode (if memory serves... it might actually be something I talk about more in the Empedocles episode) is that Empedocles' proposal is not the same as Darwin's, and that the selection mechanism is what you need to add to randomness to get a proper response to Aristotle. Aristotle is right that invoking a random process, and nothing else, is an inadequate way of getting to the regularities we see. The modern theory of evolution actually adds two things though, namely natural selection and a genetic account of how traits that have been selected are passed on to subsequent generations.

Even then, you would I think be right to resist the idea that evolution shows we should "dismiss" Aristotle because as I think I've also pointed out in the podcasts, it depends on how we understand final causation. It might be that even contemporary biologists would not be able to eliminate talk of purposes in their explanations of nature. Even if there is also a historical account of how purpose-fulfilling traits emerged, this would not make such explanatory talk useless. (That is, we can admit that the giraffe's long nneck is the product of evolution, while still saying that it serves the purpose of allowing it to reach leaves.)

Best wishes,


morgan 14 January 2015

In this podcast you said (~16:00), "make enough incremental changes across the generations, and you can turn apes in humans, as Darwin taught us". However, I don't think strictly that Darwin taught us that. Rather, we both incrementally changed from a common ancestor. Just a minor point. I'm thoroughly enjoying the podcast.

If apes and humans derive from a common ancenstor, then it follows by the axioms of Darwinian evolution that both derived from that ancestor in a number of incremental steps. In that sense it must be right that you have to make "enough incremental changes across the generations": Do some 'backwards' and some 'forwards' and you have an unbroken line of incremental changes that connects humans and apes.

I think Peter's statement is also true in a stronger sense: Darwinian evolution, is in principle not only analytically but also practically reversible, given just the right selective pressures. Therefore it follows logically that - given enough time for incremental steps and just the right selection pressures - apes can turn into humans. Furthermore, there is nothing in the theory of Darwinian evolution that is preventing apes to evolove into humans on some other route in Darwinian evolution.

So, while Darwin didn't teach that humans evolved from apes, his theory implies, basically, that all living beings could evolve into all other living beings. One just have to bear in mind that, given the space of possible directions to take in evolution and the necessity of the exact selective pressures, the chance for that is infinitesimally small.

So, I think in this way Peter is quite right when he says "make enough incremental changes across the generations, and you can turn apes in humans, as Darwin taught us". Besides his theory, which allows for such changes, and which the moidern synthesis does as well (one would have to turn to Evo-Devo approaches, I think, to have a theory that prohibits the reversion of certain evolutionary changes.

Incidentally, this brings me to think about the role of final causes in modern evolutionary biology: I'd claim that it makes ample use of those as oftentimes we know the later forms of living beings far better than the earlier ones. When figuring out how form x evolved into form y evolutionary biologists don't, usually, refer to the earlier form x and the selective pressures z exclusively in their starting point and then show how x, z -> y. Rather they start with x, y and then try to figure out which incremental steps must be taken to get from x to y. Then, once that is done, they ask for the selective pressures necessary to make those steps a plausible route. So, while they present in the end something like 'x, z -> y' as their result, I'd think that a lot of actual explanatory work is done in arriving there by utilizing the final form y as a final cause. Maybe Aristotle wouldn't have had much of a problem with that - I think it doesn't fit so badly into his scheme of explaining nature.

Those are some interesting points. I suppose you are correct, that Darwin didn't teach us that apes evolved into humans, but that he did teach us that apes could evolve into humans. The comment stood out to me because so often people will incorrectly remark that man descended from the apes. But under the right conditions, perhaps a "highly evolved" creature could evolve (devolve?) into algae, although the odds of that reminds me a little of the odds of monkey typing out Hamlet, given enough time.

One thought I had in regards to your comment about modern evolutionary biology, and I could easily be wrong, is that biologists have lots of information about form y, less information about form x, and even less information about pressure z. X might be a fossil or living creature, y might be a fossil, but z might be what? I'm not sure, but I'd guess most of the microclimate/micro environment information isn't readily available, and possibly depends on fossil records. So z is concluded from y and x. I'd guess it is presented as 'x, z->y' because z would be a cause of y incrementally changing to x. But it does seem to put the conclusion before the premise, so to speak.

Thanks to Mr Lührs for leaping to my defense: I think he is also right, but I should plead guilty on the original point, since I was speaking too loosely there and clearly did at least imply that as a matter of fact humans descended from apes. Too late to change it in the book version, too, sadly.

Peter Lührs 18 January 2015

In reply to by Peter Adamson

You are welcome: I really try to 'respect the text' and it seemed to me to be the most charitable interpretation of said sentence. Still, kudos for taking responsibility for 'speaking too loosely there'.

@Morgan: Yes, I think that's basically the reasons why evolutionary biologists reason like they do, but present the accounts of evolutionary processes in a different order.

Greg Hunt 27 January 2016

Hi Peter,

I'm currently reading Armand Marie Leroi's The Lagoon, which is all about Aristotle's biology. I think it's fascinating, as he draws parallels between Aristotle's research and modern science, pointing out his mistakes and achievements. 

I was wondering whether you had read it and what you thought of it. One thing is that the author is very dismissive of Plato.



Peter Adamson 27 January 2016

In reply to by Greg Hunt

I actually do have a copy but have only paged through it briefly (in part because I got hold of it only after covering Aristotle's biology here on the podcast and in the book version so I have been frying other fish). But it does look interesting, I hope I will get around to reading it soon!

Permapoesis 26 July 2017

OK, my comment a few episodes ago was perhaps a little off mark, as far as Aristotle and the biophysical was concerned, and I thank you Peter for painstakingly unpacking this philosopher who marks a next notch in philosophy's complexes that I admit I'm struggling with. Dazzlingly confused at times I nonetheless go back and re-listen to certain episodes and can generally see more clearly for the effort. It really feels like I'm being encoded in yet another layer of abstraction, rarer than most other mediated substances that form the cultural psyche I was born into. However, a question continues to arise: Since Hesiod accused Pandora (first mortal and therefore mother to humans like Eve) as the evil fermenting witch who brought disease and other ills to men, western thought really has been radically gender lopsided, as this podcast series to date attests. It is strange that while James Brown to referred to in relation to Aristotle's soul, albeit flippantly, the fore place of misogyny in all this thinking (since Hesiod poetically-religiously and Thales philosophically) is bordering on suspiciously absent in the discussions. It is like the absence of women is a given. So strange. This seems to be a very big gap. There is not even an episode dedicated to Diotima of Mantinea (although she was referred to briefly in the Platonic run). While matriarchal Greek wisdom was oral and we don't have texts to refer to directly, this doesn't make it impossible to draw on it as an actual part of our heritage. We have drawings, vases, artefacts and other things to draw on to speak to female wisdom which I would call performed philosophy. So, my question is, if James Brown can be referred to from the vantage place of the future, why not Luce Irigaray?

Actually as you'll go on in the series you will see that I have made a big deal about emphasizing the role of women thinkers, especially in the medieval period. The book version of the Classical Philosophy part also adds a chapter on women in ancient philosophy, which discusses Diotima among other figures.

Permapoesis 26 July 2017

In reply to by Peter Adamson

I suppose my questions are about origin. Why begin with Thales? What stood behind him, what and who stood behind patriarchal Greece? And now we know that this early period of formalised thought is lopsided and often misogynistic in form, why not address this, why don’t we 'fess up to it? It's really the culture I'm questioning here, the absence of the mother, the absence of the flowering-fruiting earth that makes philosophy and every other thing possible. Not one single philosopher in the series to date mentions the definitive place of the mother. They can’t all have been raised by wet nurses, and even so where’s the exploration into surrogacy? So what lies beneath all this rationalism, this innovation anxiety, this detachment from the corporeal, the everyday? What does it stand upon? That patriarchal thought exists is accepted, but why does it exist, how does it exist? This seems to be an important question for the history of philosophy.

Peter Adamson 28 July 2017

In reply to by Permapoesis

I have a certain sympathy with what you're saying insofar as it is really important to me to get away from the exclusion of women from the history of philosophy. However, I have only a limited sympathy for the idea that philosophical ideas are always patriarchal or misogynist simply because they emerged from patriarchal and misogynist cultures (which means, pretty much, all cultures that have existed so far). It's for sure true that Aristotle was able to do what he did in part because he was a rich man, not a slave, laborer, or woman. But does that mean that every idea he had is somehow stained by the injustice of his culture, so that for instance the syllogistic theory is inherently "patriarchal"? I'm dubious about that. I do try to place philosophy in its historical context in the series but I think it is a mistake to reduce philosophy to being nothing but an expression of the historical injustices that can be found in the context.

Regarding talk about nature using maternal metaphors, as you suggest: as you'll see later in the podcast (or already heard in the one about the Timaeus), we find such metaphors in texts by patriarchal aristocratic men, and actually I think there is a latent sexism in a lot of those metaphors - the maternal is the passive or material, which submits to the creative force of a divine Father. Probably that is not what you mean by the "definitive place of the mother" but it is the way the metaphor usually turns up in ancient and medieval philosophy.

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