Current Projects

I  Ancient Philosophy & Science

Aristotle's Worst IdeaThis is an exploration of the idea that I call 'monotelism' – the idea that every natural organism or process properly has one and only one purpose or function. Though this idea is not original to Aristotle, he was perhaps the first explicitly to enunciate and defend it (though he freely admits that there are some cases where nature has been constrained to double up its ends for a single means). I argue that this idea worked its way deep into the western intellectual bloodstream, where it has done much damage to our thinking on such subjects as gender, sex, money, and labour. Most recently, it was the error that lay behind the massive overestimation of the number of genes that would be discovered in the human genome. I have spoken frequently about this in recent years, at the Western CPA, at Dalhousie University, at Trent University, at York University, at the University of Toronto, at Middlebury College, at Louvain, at Texas A&M, and elsewhere. An early poster presentation of this idea is here.

Sex & Mysticism in Plato. This talk, given to the Society for Ancient Greek Philosophy some time ago, is about Plato’s epistemology. It is standard to think that he had two different ideas about how we come to know the Forms: anamnesis — remembering things from our preincarnate state — on the one hand, and inductive abstraction from sensory experience on the other. This paper argues that there is a third idea, distinct from the first two, at work in Plato’s thought: we secure knowledge of the Forms (and especially the highest ones) in moments of mystical intuition. The paper explores Plato’s mysticism, and in particular its connection with sexual erôs. The SAGP has archived the paper here. An updated and condensed version was read to the Faculty de Filosofia y Letras of the Universidad de Buenos Aires, in July 2017, under the title ‘Eros y misticismo en la epistemología de Platón’. Available here 

Plato’s Bed: Essence and Archetype in the Theory of Forms. This talk, which was a contribution to a Greek Philosophy Workshop at the Universidad de Buenos Aires in July 2018, makes fresh trouble for Plato’s Theory of Forms. It argues that Plato never really distinguished two different conceptions of a Form: is it an archetype, that is, a supremely marvellous exemplar of a given kind? Or is it an essence, that is, the necessary and sufficient conditions for being of that kind. Is the Form of Bed the idea of the most perfect of all possible beds, or is it just the bare-bones definition of bed? There are texts pulling in both these, opposite, directions. Moreover, if essences are what Plato really wants the Forms to be, he does not seem to have realized that such entities would have many indefinite properties. The Form of Bed would have the property ‘wooden’, but it would not be of any particular wood — oak, olive, beech…. But, then, can something with indefinite properties be said to exist? Can anything be coloured without having a specific colour? A poster version of this talk, in English, is available here,

Postmodern Aristotle? There is an old and well-worn discussion about how Aristotle understands our knowledge of the axioms, or first principles, of a science. Some texts suggest we have them by a kind of self-authenticating intuition, which he calls nous. Other texts suggest that something much more like induction is at work. There is now broad acceptance of the idea that the way to reconcile these two different ideas, is to say that we acquire our knowledge of the axioms by induction, but that their warrant lies with nous. I argue that this discussion has overlooked a third idea on this subject that can be found in Aristotle, namely that we ground the axioms by dialectical argument. He says this explicitly in a rarely noticed text of the Topics; more strikingly, though, it is his own practice when he comes to justify the axioms of the science of logic, that is, when he defends the Principle of Non-contradiction and the Law of Excluded Middle. This gives the striking result that he sees science as like a mediaeval cathedral: an imposingly solid and rigid building of stone, set on wooden piles driven into the soft earth. I have spoken about this at conferences in Edmonton, in London, and in Milwaukee. A poster presentation of the argument is available here.

'Aristotelis corruptus'. The metaphysical system of the Categories seems to fall apart over the status of differentia: is it in the category of substance, or the category of (typically) quality? Plotinus seized on this difficulty and used it to argue that Aristotle's nominalist metaphysics was incoherent. Porphyry considered the matter and decided that differentia belongs not, pace Aristotle, in the category of substance, but in some other category, usually quality. Since the categories other than substance came to be called 'accidents', this generated, in the later Aristotelian tradition, the result that some accidents were necessary — and that seems an outright abuse of language! I argue that this development represents a debasement and corruption of Aristotle's original theory of the Categories, a theory which was both subtler and suppler than even the early tradition understood. I base my argument on a quite unambiguous but little known text of the Topics. I have spoken about this at conferences at Guelph University, at Dalhousie University, and at the University of Lethbridge, at the 2010 Ancient Philosophy Society meeting at Michigan State University, and at the 2012 inaugural meeting of the Canadian Conference in Ancient Philosophy in Edmonton. With a different slant I have presented some of these ideas at the Minnesota Philosophy Society, at McMaster University, and at the Canadian Philosophical Association. And a yet newer treatment of the same clutch of texts and troubles, under the title Saving Aristotle’s Categories, was read in Vancouver in 2015.

Aristotle on Natural Justice. Aristotle is generally claimed as a progenitor of natural law theory. His one chapter on this subject, Nicomachean Ethics V,7, is in fact very short, very compressed and very difficult. It appears to maintain that natural law — or, more strictly, natural justice — is variable; this is, to say the least, a surprising idea. It has given birth to a wide variety of suggested interpretations. I argue that the text in question has been  misinterpreted, by virtually all commentators. A correct reading gives us an Aristotle who, far from thinking that there are some transcendent and immutable principles of justice, sees those principles as all immanent and variable. Aristotle in fact roundly rejects the characteristic ideas of natural law theory: not only is he not a founder of the natural law school; he is not even a member of it. I have given versions of this talk at conferences in Victoria, in Halifax , at the Society for Ancient Greek Philosophy in New York, and at the Ancient Philosophy Society in San Francisco. A poster summarizing part of this argument, under the title ‘Aristotle & the Tyranny of Nature’, is available here

Aristotle’s Definition of Time. “Time”, said Aristotle, is "number of movement with respect to before and after” and, so saying, he unleashed more than two millennia of puzzlement among commentators, some of whom have offered decidedly complex, almost acrobatic, interpretations. This paper points out a little-known use of the word ‘number' (arithmos) in the 4th century BCE, and argues that if we take that meaning of ‘number', the puzzle dissolves. This paper was read at the SAGP/APA meeting in Kansas City, March, 2017, and at the Classical Association of Canada meeting in St John’s a few months later.

Aristotle and Code. Aristotle had many firsts to his name, of course; I argue in this paper that one piece of originality which has not been noticed is his rather tentative exploration of the idea that we would now call ‘code’ — a system for transmitting information in a physical form that is different from that in which it enters or exits the system. An example of an artificial code is language: speakers encode mental states as sounds (and maybe also written marks) for transmission; hearers of these sounds then decode them into the appropriate mental states. Natural codes are hypothesized by Aristotle in his account of various facets of cognition, on the one hand, and, on the other, in his account of animal nutrition and reproduction. In these latter cases he uses the word kinêsis for the code (or its vehicle). This paper explores various facets of Aristotle’s rather tentative groping after the idea of code. Versions have been read at the Canadian Philosophical Association in Waterloo, and at the SAGP in San Diego. A poster version of the paper is available here. The paper itself is here.

Aristotle’s "clivus naturae". In de Anima Aristotle appears to be urging a view of the soul according to which its various parts or levels, though cumulatively arranged, are in themselves indivisible and discrete: it is the scala naturae of psychology. But when it comes to close empirical work, in for example the Historia animalium and the de Partibus animalium, he seems to want to moderate this picture, and to see nature ascending, not in discrete steps, but continuously (συνεχῶς) through the various degrees of vitality, with the boundaries between the levels of soul becoming blurred. This is a picture not of a scala naturae but of a clivus naturae: not a ladder of nature but a slope of nature. This paper explores these different images and the tension between them. It was presented at the meeting of the Sociedade Ibérica de Filosofia Grega in Lisbon in April 2016 (here), and at the Classical Association of Canada the following May; a poster version is available here.

Aristotle, Females and Wind-Eggs. Aristotle is often cast as a misogynist, but actually the situation is worse than that: he is a misothelist: he disprizes not just women, but females in general. This paper explores what I take to be one of the sources of that attitude — the phenomenon of wind-eggs. Wind-eggs are the unfertilized eggs of a number of fowl (Aristotle mentions hens, peahens, pigeons, partridges, geese, and shellducks); what is striking about these wind-eggs is that they differ scarcely at all in size from fertilized eggs, but what they lack is any potentiality for life. This will have seemed like incontrovertible evidence that the female bird contributes virtually all of the matter in generation; the male contributes scarcely any matter, but only the life-potency, i.e. the form. This dramatic conclusion, which has rung down the ages to Aristotle’s discredit, does not, of course, long survive his worries about the inheritance of maternal characteristics. This paper has been given at the Classical Association of Canada in St John’s Newfoundland, and at the SAGP in New York. A poster version of the argument is here.

Aristotle and the Physiology of Sense Organs. This paper is not about the metaphysical debate between ‘literalists’ and ‘spiritualists’ in the interpretation of Aristotle on sense perception. Its concern is narrower: how do sense organs work — just at the physiological level? The answer it urges is twofold. a) The organs really do take on the feature of the perceived object — eyes become coloured, tongues tasty, and ears noisy. And b) the organs are physiological homeostats, endowed with a mechanism that is always seeking to keep them in the middle, undetectable, state, halfway between the contraries that define their proper objects. This paper was read at the meeting of the SAGP in January 2015, in New Orleans.

Aristotle on Intelligible Matter. The oxymoronic phrase 'intelligible matter' occurs three times in Aristotle, twice in Metaphysics Z and once in Metaphysics H. In the first two passages it has the same meaning; in the third the meaning seems radically different. This gives the impression that the Aristotelian language of metaphysics is distressingly slack. I argue, against the nearly unanimous voice of two millennia of commentators, that 'intelligible matter' has the same meaning in all three loci. This argument allows me to develop a capital distinction that tightens up the apparatus of aristotelian metaphysics. I have given this talk at the CPA in Ottawa, and at the SAGP/APA in San Francisco in 2010. 

Aristotle's Rhetorodicy. There has long been a puzzle about Aristotle's apparent change of heart about the moral status of rhetoric. There is good evidence that, in his earlier career, he shared Plato's animus against rhetoric as the tool of deception. But, then, later, he seems to have changed his mind, and he wrote one of the best rhetorical manuals of antiquity. How did the later Aristotle justify this change of view? This paper draws attention to two astonishing passages in the Rhetoric that have been largely ignored by commentators, passages suggesting that rhetoric might well be understood, not as a tool for deception about the truth, but as a tool for the discovery of the truth. This talk has been given at the CPA in Fredericton in 2011, at the SAGP in Philadelphia in 2012, and, in a somewhat different version, at Texas A&M in 2013, and at the Classical Association of Canada in Montreal, 2014. In a much-revised form it was given at the 2019 Ancient Philosophy Workshop at the Universidad de Buenos Aires, under the title ‘Aristóteles, Retórica y Probabilidad’. A version of the paper is available here.

Aristotle on Ontological Truth. Much of what Aristotle writes on the concept of truth seems comfortably familiar; it amounts to a rudimentary correspondence theory under which only compound linguistic items — sentences —  can be true or false. But here and there in the Corpus, and especially in Book Theta Chapter 10 of the Metaphysics, he introduces some troubling thoughts. One is that uncompounded items can be true or false. Another is that the things, whether compound or simple, to which true words correspond, can themselves be true or false. And then, interwoven through several texts is the idea that truth is a part, or sense, or aspect, of being. This paper examines a number of ways in which philosophers over the centuries have tried to understand this strange material — Aquinas, Brentano, Heidegger — and finds them wanting, before going on to present a new theory. I have spoken on this subject at the Classical Association of Canada, and at the SAGP in Seattle in January 2013.

The Heat and Light from the Stars. This paper (which is essentially a retraction of the central idea in an article I published three decades ago) addresses the longstanding question of how Aristotle thought that the heavenly bodies produce heat and light. He says a number of times that the stars are not themselves fire or fiery; rather they rub on the air beneath them and so produce fire. The problem with this is that, according to the normal understanding of the structure of Aristotle's cosmos, there is no air just beneath the stars for them to rub against. Solving this problem leads to some significant revisions in our understanding of Aristotle's physics. I gave this talk at Marquette University in June 2011.

Homeopoiesis: Aristotle & Cancer. This paper seeks to understand how Aristotle's ideas about nutrition avoid cancerous growth: why does the flesh that is distilled out of the digestive process, and that travels out to the various parts of the body, not just produce formless growth? Why do our fingers not become longer and longer throughout our lives, or our eyelids heavier and heavier, or our earlobes great sails on our heads, or our tongues swollen up to fill our mouths? Pulling together texts in the de Generatione animalium and the de Generatione et corruptione I try to piece together Aristotle's schematic account of this process. This paper was read at the SAGP/APA meeting in Chicago in February 2012. A version of this, from a rather different angle, was presented in the form of this poster at the Canadian Colloquium on Ancient Philosophy, Vancouver, 2014.

On Hobbes' ‘Aristotelity’. In Leviathan Chapter xlvi Hobbes sneeringly dismissed the university curriculum of his day as not philosophy but ‘Aristotelity’ — slavish adherence to the doctrines of Aristotle —  and he deployed a sizeable list of particular objections. This paper examines three main foci of his scorn and asks the question whether, in each case, the object of his disdain was genuinely a teaching of Aristotle. In other words, it asks the question: “How aristotelian was Aristotelity?” Not surprisingly, it turns out that Aristotelity was, in general, a fairly crude and unsubtle version of Aristotle. This paper was read at the Dominican University College in Ottawa in autumn 2014. A version of the paper is forthcoming in Science et Esprit.

Transcendence: from Light to Darkness. In Plato, the moment of reaching knowledge of the Ultimate — the Form of Good — is described with language about brightness and light. Half a millennium later, in Plotinus, the language about the Ultimate — the One — turns to darkness and silence, to ineffability and transcendence. And so begins the tradition of mystical or apophatic theology, in which we find such figures as St Gregory of Nyssa, Pseudo-Dionysius, Damascius, etc. Theology and philosophy turn weird, if darkly alluring. This paper, given at a conference on Transcendence in Ancient Philosophy in São Paulo in 2022, is broadly deflationary in intent. It distinguishes among three different types of cognitive transcendence; it argues that much that seems mysterious in Plotinus’ claims about the One can be understood as what, in philosophy of science in our own day, is called ‘theoretic necessity'; and it takes the sting out of the idea that something may be said to be ‘beyond being’. 

Vitruvius' Vases. Vitruvius famously proposed the use of resonating vases as sound-amplification systems in ancient theatres. This paper studies the detail of his proposal, and understands it against the background of Aristoxenus' musical theory. It draws some rather definite conclusions about musical practice in antiquity. I have given this talk at the University of New Brunswick, as well as to some local audiences. A poster version is available here.

II Philosophy of Religion & Theology

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The Real Presence without Aristotle. Popular understanding has it that 'transubstantiation' is a matter of Roman Catholic dogma. This, however, is not true: the Church has long insisted on the Real Presence of Christ in the consecrated elements, but has stopped short of requiring that this be understood and expressed in the Aristotelian language of substance and accidents. Given that the metaphysics of substance and accidents is now a philosophical museum-piece, this paper enquires whether a credible interpretation of the Real Presence can be elaborated using more current metaphysical apparatus. With recourse to such concepts as performative utterances, pragmatics of language, and intrinsic properties, I work out an understanding of the Real Presence which (I believe) avoids falling into the well-populated category of flaccid cop-outs – the category containing such views as receptionism, virtualism, transsignificationism, and the like. The idea of the Real Presence has always been a bracing idea for philosophy, forcing, as it does, an exploration and negotiation of metaphysics at its deepest level. This is no less true now, with our very altered metaphysical horizon, than it was in the ages when the metaphysical system stemming from Aristotle articulated the common understanding of the world. I have given this talk at Campion College, Regina.

The Evolutionary Argument against Naturalism. This paper considers Plantinga’s famous evolutionary argument against naturalism, and explores how well it survives Daniel Kahneman’s distinction between the two human cognitive systems. System 1, which is the rude deposit of natural selection, favours survival and reproduction over the targeting of truth; system 2 — which may be an evolutionary spandrel — is often critical of system 1, and seems to target truth over simple survival. These results from Kahneman’s work are, I argue, lethal for Plantinga’s argument. This paper was read at the June 2015 meeting of the Canadian Society for Christian Philosophy.

Soft God, Hard God. Theologians are divided about the concept of omniscience; some take it that God’s omniscience implies that s/he knows all things; others settle for a softening of the concept and say rather that God’s omniscience implies only that s/he knows all things that can be known. (Among the things that purportedly cannot be known, here, is the future.) Interestingly, though, there has been little in the way of a parallel dispute between hard and soft versions of omnipotence: most theologians take it that God’s omnipotence means that s/he can do all things that can be done. And excluded from things that can be done are logical or mathematical impossibilities. Almost no theologians have opted for hard omnipotence, that is, for the idea that God can — among other things — instantiate contradictions or make π rational. I argue that soft omnipotence is, in various ways, inadequate as a divine property. This paper was given at the conference on 'The Idea of God' in St John’s, Newfoundland, in November 2016, and to a Reseach Forum in Theology at Huron University College in April 2017. A substantially revised version was presented at the University of Malta in November, 2019.


A Mistake about Grace.  This is a deflationary paper about the concepts of sacrament and sacramental grace. Using the idea of the performative utterance, it explores the logical peculiarity of a 'sign that effects what it signifies'. It resists the colourful plumbing metaphors that are part of standard language about sacramental grace, and construes such grace as nothing more than 'what the sign signifies'. Investigating some texts of St Augustine, it further deflates the traditional understanding of the contrast between the 'outward and visible' and the 'inward and spiritual'. This talk was given to a joint meeting of Anglican and Roman Catholic seminarians in London, Ontario.

The Great Burkha. Towards the end of his book The God Delusion, Richard Dawkins develops the following simile. Our human understanding of the world, until the last century or so, has been like that of a woman seeing the world through the narrow eye-slit of a burkha: our horizons of understanding have been very limited. As science has probed the world of the very small, and also the world of the very large — as the burkha eye-slit has been widened — we have come to see that we cannot simply project the logic of middle-sized objects onto those other scales. This paper argues that traditional theology suffers from confinement in a burkha: it repeatedly insists on confining God within the logic of middle-sized objects. But whatever logical constraints apply to God, they must surely be at least as permissive as those that constrain the universe, small, middle and large. I have given this talk to a number of local audiences.   

Secularism: Two Concepts, Two SourcesThis paper elaborates two different conceptions of secularism, which I call vertical secularism and horizontal secularism. Vertical secularism is a system of thought in competition with religions — it is, if you like, the religion of atheism, the religion of irreligion. Horizontal secularism, by contrast, defines the shared space in which members of different religions may have some part of their life in common: it is notionally agnostic; a plural society requires it. These two different conceptions are traced back to the two rather different co-founders of the secularist movement in England of the 19th century, Charles Bradlaugh and George Jacob Holyoake. I have given this talk at the Université de Sherbrooke, as well as at conferences at McGill University, Huron University College, and the University of Hawaii.

Ethics, Sex and Religion: a tectonic shift. This was the Kenneth Mark Drain lecture delivered at Trent University in November 2013. Beginning with an observation about how far religious and secular ethics have come apart in recent decades, it explores the conceptual terrain surrounding the vexed question of the place of religion in a ‘secular’ society. A version was delivered to a local audience in December 2014, under the title Athens against Jerusalem: secular vs religious ethics in the 21st century. A slightly revised version was given to the London Humanists Association in February 2015.

Grounding Liberal Theology. This paper explores the Eastern Orthodox idea of oikonomia as a grounding for liberal theology. It was the keynote address for the founding conference of the 'Widening Circle' group in the Anglican Church of Canada in 2007.

III  Other Subjects

to Sahagun copy

One Million Steps to the End of the EarthThis talk is a ruminative travelogue about the pilgrimage to Santiago de Compostela which I walked in 2003. It explores such subjects as Spain's surprising alliance with the US in the invasion of Iraq, and its background in the reconquista of the 9th century; Goethe's oft-quoted but little-understood remark that Europe was founded on the pilgrimage to Santiago; and the mystical idea of walking as 'resting in'. This was the MacKay Lecture at Dalhousie University in 2004, and it is a talk that I have often given more locally.

What are the Liberal Arts? This talk resists the common idea that the liberal arts are called 'liberal' because they are somewhat easygoing: they lack hard-edged objectivity, they have about them a certain pliability, a certain softness — essentially, they are free of mathematics. How strongly this picture contrasts with the classical and mediaeval lists of the seven liberal arts: logic, grammar, rhetoric, arithmetic, geometry, astronomy and music! Of these, six are mathematical in nature. Music was audible arithmetic; astronomy was visible geometry; logic and even grammar, too, were subjects with hard-edged, unyielding, right-or-wrong answers. Rhetoric alone was somewhat pliable. This paper expounds the history of the phrase 'liberal arts', and shows that the source of the term lay in the idea that these subjects were fit studies for a free citizen – hence 'liberal' – as opposed to subjects befitting a slave, the 'servile arts'. The paper further argues that the most promising way to defend the liberal arts in our present context is to re-engage this original meaning of the phrase. This paper was given at St Thomas University in Fredericton in 2010. A poster version of the paper is available here.

A Suspicion about Determinism. This talk reflects on the fact that the idea of determinism, or fatalism, keeps recurring in very different contexts, at different times: logical fatalism, theological fatalism, physical determinism, psychological determinism, etc. Standing back and looking at this big picture, it voices the suspicion that all these different determinist theses, arising in different intellectual soil, are all manifestations of a single, deeper, conceptual trouble. I have given this talk locally several times; a poster version of it is available here.

Freedom and Probability. Philosophers who want to defend the idea that we humans have free will (in the sense of free choice) find themselves struggling against causal determinism, in one or other of its many guises. Broadly, determinism is the idea that there are laws at work in the universe that make the outcome of a choice absolutely inevitable, despite our intimate sense that it is not. Many such philosophers are driven to embrace indeterminism, the idea that there are breaks in the chain of causal links leading up to the making of the choice. There are well-known problems with this idea, of course, but there is also a problem that is less well known. Postulating indeterminacies might free us from strict causal laws, but it doesn’t help in freeing us from probabilistic laws. And most of the laws that seem to cover our behaviour are probabilistic ones: the laws discovered in psychology, sociology, economics, longue durée history and so forth. Perhaps philosophers should shift their focus from “freedom and determinism” to “freedom and probability”. This paper was given at the Institute of Philosophy in Zagreb, in May 2018.

Causality and Explanatory Priority. The question of this paper is whether, as we learn more and more about neurophysiology, and more especially about neuropsychology, it might nonetheless be possible to think that, at least sometimes, (pace Libet) the mind runs the brain. I develop a model for what I call ‘explanatory priority’. Assuming that mental states and their correlated brain states are simultaneous, we are dealing here, not with two different states, but with two different descriptions of one and the same state. It is then inappropriate to think of the one description ‘causing’ the other. However, it appears that one description may have explanatory priority over the other. I may lose my headache because of the chemical changes resulting from taking an aspirin; or dopamine may flow because I had a cheerful thought. The priority in each case is not so much causal as be-causal. The conditions for this explanatory priority, this be-causality, are explored. This paper is part of a conference on Free Will and Causality at the University of Düsseldorf in September, 2019.

Universal AccidentsThis paper (originally written with William Vanderburgh) proposes and defends the idea that the (apparent) universality of contingent laws of nature can be understood as the result of the spread of a local accident. An analogy is developed with the historical spread of certain features of language which began as contingent features of a local language, and then, through the vagaries of political or cultural conquest, spread more broadly among peoples. This talk has been given at the Philosophy of Science Society in Brussels, at the CPA in St John's, at the University of New Brunswick, and at Trent University.

The History of Usury. This talk began in the realization that in the thirteenth century and before, usury was regarded as an extremely despicable crime — not just something you shouldn’t do, but something deeply disgusting:  Dante punishes usurers even lower in hell than sodomites. In dramatic contrast, bankers are now generally admired (except perhaps since the economic crisis of November 2008). With a series of soundings of texts in moral philosophy, texts in law, and theological writings, I trace the 180° turn in popular morality that this constitutes. This talk has been given a number of times to local audiences. A partial version is available as a poster here.

© John Thorp 2014