From Sixsigma
Jump to: navigation, search

PHI130 Essay 2


Write a 1500 word essay. Draw on the relevant readings from the unit and on the material discussed in lectures. Include your own thoughts and/or responses to the readings and lecture material.

Topic: Cartesian Dualism

Why, according to Descartes, must we understand mind and matter (body) as different substances? Explain and evaluate the reasons he uses to defend this position, and compare it to the physicalist account of the relationship between mind and body (taken from the Nagel or Churchland articles in your Reader). Clearly state which account you think is best and explain why.


Descartes holds that mind and matter are two distinct substances (Descartes 1641). If he'd used precisely those words, and said no more, there would be a way to find his conclusion true under interpretation (albeit with a somewhat modified conception of substance as context affinitive), especially if he'd deigned to declare it simply as axiomatic. Alas, he expounded on this simplified expression of his idea and in his effort to demonstrate just cause betrayed his view as confused, indefensible, and ultimately irreconcilable with a consistent and positivist account of reality, as was ostensibly his aim. Particularly, his attempt to find distinction in the necessarily opaque realm of substance is unfounded, and of essence an abuse of language.

Descartes was a Frenchman, living from 1596 to 1650, in a place and time where philosophical inquiry had been heavily dominated by the scholasticism of the Catholic church. Descartes was schooled by Jesuits, and demonstrated a marked tendency throughout his life to foster good relations with the church (Williams 1978). In such alignment the object of his salient work -- Meditationes de prima philosophia, as originally published in 1641 in Latin -- was primarily to set out a proof for the existence of God, and for the immortality of the human soul: "in qua Dei existentia et animæ immortalitas demonstratur."

As is typical of modern philosophy, the founder of which Descartes himself is often held to be, the social process of legitimation demands claims to knowledge to be codified and presented as rigorous "logical" formulations given to inhere in a vast smattering of words, thus his Meditations. Masked in his impressive and complicated verbiage is his case for mind/body dualism, there stated indirectly amongst a slew of cognitive exercises as a would-be logical system of relations and derivations, rather than directly as assertive claims of intuitive conception. In presenting his case for the substantive nature of the dual concepts of body and mind Descartes invokes two arguments, so called: the 'indubitable' argument, and the 'self-knowledge' argument; the latter in its more refined form being known also as the argument from introspection. Further to Descartes' own arguments for the dualist theory of body and mind are the argument from religion, and the argument from irreducibility (Churchland 1988).

Indubitable means: beyond doubt. Descartes finds that where he is able to doubt his body, he is unable to doubt his mind. According to Descartes this is because 'doubting' requires the 'doubter'; that is, the mind. Where, by his intuitive conceptions (so being conveniently and compatibly aligned with Christian doctrine), the body is allocated the property of being doubtful, and the mind the property of being beyond doubt, then by Leibniz's Law concerning the identity of indiscernibles this ontological incompatibility is held to give rise to a proof of distinctness.

While one might be inclined to think that conceptions being distinct does not by necessity imply they are substantive; or where one might believe that the referent of the term "substantive" is that which "stands under" the observable, or even the referable, in the universe; Descartes would contradict such a conception of these very terms and lay claim to knowledge of diversity in the substantive realm: "we are necessitated to conclude, that all those objects which are clearly and distinctly conceived to be diverse substances, as mind and body, are substances really reciprocally distinct."

One retort to the indubitable argument is that, similarly to the argument from religion, it proceeds from primitive theoretical conceptions taken on faith. An example of the type of logical error that can be masked by such an argument is shown by this pithy demonstration taken from the lecture notes: "I believe Marilyn Monroe was a famous movie star; but I don't believe Norma Jean Baker was a famous movie star; so Marilyn Monroe is not the same person as Norma Jean Baker!" The mistake here hinges about the fact that Norma Jean Baker's screen name was Marilyn Monroe. Marilyn Monroe emerged from Norma Jean Baker, as an aspect with new properties. Norma Jean Baker stood under Marilyn Monroe as the substrate, the platform, the substance. (But it's all make-believe, isn't it?)

The argument from self-knowledge, or introspection, asserts that "the mind" (held as distinct and independent from the body by hypothesis) can know itself with certainty, whereas "the body" (drawn as distinct and independent from the mind by hypothesis) can not. The central trouble with this argument is that it isn't one. Rather, it is a claim to intuitive knowledge of a thing called mind, and a thing called body, where it is alleged that per the experiential phenomena unfolding in Descartes' own mind the thing called mind is apprehended "clearly" and undoubtedly, as contrasted with a reciprocal "cloudy" and doubtful conception of the body. Descartes again invokes the possibility of doubting the body, and the impossibility of doubting the mind. It is doubtful he was so enlightened as he imagined. Descartes' observation of the more "perfect" or "pure" knowledge of mind seems to echo Plato and his realm of forms. Descartes grants the concept of mind a purity he withholds from the body, thereby elevating the status of its conception.

In his argument from self-knowledge Descartes argues the category error that as he "knows only that he is thinking" he knows that "he is only thought", and thereby he identifies with his mind. As he takes his identity to be his mind, and as he does not deny the possibility of the body (though the body might be a deception), he concludes that the mind is a primitive conception (substance) of a different kind to the body (which he accepts also as substance).

Ryle famously objected to what he dubbed Descartes' Myth, the dogma of the Ghost in the Machine (Ryle 1949). One of his arguments, known as Ryle's regress, is that the concept of the conscious mind can not be one where a man considers how it is that he considers, as he would then need to consider how he considers how he considers, ad infinitum, lest he resign himself to unconsciousness. Ryle's complaint in turn echoes the ancients, in this case ringing of Zeno and his paradox of Achilles and the tortoise:

The crucial objection to the intellectualist legend is this. The consideration of propositions is itself an operation the execution of which can be more or less intelligent, less or more stupid. But if, for any operation to be intelligently executed, a prior theoretical operation had first to be performed and performed intelligently, it would be a logical impossibility for anyone ever to break into the circle. (Ryle 1949, p. 30.)

Mind-body dualism is perhaps best sympathised with by taking consideration of its historic context. It arose as a theory in which the Catholic tradition might seek refuge from the ideas and practices inherent in the onset of Modernity. The emerging and dynamic structure of power and its forms of legitimation themselves catered to the promulgation of this idea. It offered the impression of a sound basis from which the church could maintain its primacy in the face of scrutiny and doubt, and thus became widely advertised. Various intellectual developments over the centuries subsequent to Descartes did much to undermine its presumed validity, however. Such developments include, but are not limited to, Einstein’s theory of relativity, quantum electrodynamics, Gödel’s incompleteness theorem, Turing’s halting problem, category theory, and Shannon’s theory of information.

It is difficult to approach the content of mind, or the content of body. To borrow from Hofstadter: they're meta-circular. The mind emerges from physicality, but in turn the mind conceives everything, even physicality, as objects of the mind. In this author's view the apparent quandary is a consequence of the system both empiricism and rationalism hold in common: that of objectification of experience.

While the true nature of body and mind, material and soul, substance and spirit, may as yet elude us, on the issue of mind as substance we can conclude that Descartes was wrong. His idea, while novel, and worthy of contemplation, is not sufficiently robust so as to withstand serious scrutiny. Further, accepting his notion would do violence to our concept of substance, and that wouldn't do. Substance is where God is, and it's doubtful we will ever see or tell of what lies behind his curtain.


Descartes, R. (1641). Meditations on First Philosophy. English translation by John Veitch 1901.

Williams, B. (2005). Descartes: The Project of Pure Enquiry. USA and Canada: Routledge. Originally published by Penguin 1978.

Churchland, B. (1988). Matter and Consciousness: A Contemporary Introduction to the Philosophy of Mind. Cambridge, Massachusetts: The MIT Press.

Ryle, G. (1949). The Concept of Mind. USA: New University of Chicago Press edition 2002.


To answer the first question, look at what Descartes actually says in his meditation. Then look at interpretations in the lecture notes and in Churchland.

Then enumerate the objections he published with his rejoinder. That is to answer the second question.

My position: they're meta-circular. The mind emerges from physicality, but in turn the mind conceives everything, even physicality, as objects of the mind. This quandary is a consequence of the system that both empiricism and rationalism hold in common: that of objectification of experience.


Final documents are here.