Book 1. Hume’s Problems with Induction
Chapter 11. Descartes’ mind-body dichotomy
David Hume’s skepticism was in part due to the ‘mind versus body’ dualism that Descartes’ philosophy produced in Western thinking more than a century earlier. Indeed, its roots are much deeper than that, traceable to Christian thought and earlier still to Greek thought. But within modern philosophy, Descartes was certainly a source of much (unintended) confusion and contention, as well as of (intended) enlightenment in a true sense.
René Descartes considered his mind to be the most knowable of his beliefs, and sought to infer an external world including matter from such introspection. Using reasoning similar to St. Anselm’s ontological argument, he first inferred God from his own mental existence; and then inferred the rest of the apparent world from God. God, being necessarily an honest broker, was to be the guarantor that human knowledge could extend out to the external material world.
Descartes’ motive in this tortuous construct was primarily epistemological: he wished to establish the validity in principle of human cognition. However, this particular way of looking at things became a problem for subsequent philosophers – for it seemed to imply an ontological radical chasm between mind and body. One could know mind directly and certainly, but body only indirectly and uncertainly. Some philosophers began to doubt that mind and body could be claimed to have any causal relation whatever. ‘Being so substantially different, how could either domain be said to cause changes in the other?’ – so they argued.
Now, this whole problem, or set of problems, is a figment of these philosophers’ imaginations. It is a mystification, a fanciful complication. It is safe to say that it was not Descartes intention to set up a dichotomy between mind and body; he was on the contrary attempting to harmonize them, first epistemologically and thence ontologically. His presentation of the issues was not perfect; but it was an honest try that can be improved.
Phenomenology. Descartes first mistake was to effectively start with the common sense distinction between mind and body, or a mental domain and a bodily one. The mind-body distinction cannot reasonably be used as a starting point, for it is only an assumption, a construct. Armed with this awareness, the apparent difficulty is easily resolved…
If we take a phenomenological approach to the issues involved, we realize that to begin with we have a mass of appearances, some of which may seem essentially different from others. We may then, as a hypothetical way of ordering the data, well assume that the seeming difference is significant, and label one set of appearances ‘mental’ and the other ‘material’ (or ‘physical’).
This is not done arbitrarily – but so as to organize our experiences, and explain why some are clearer than others, or why some behave somewhat more erratically than others, or why some seem to us more under our control than others, and so forth. So long as this hypothesis of substantial difference serves its useful purposes, it is maintained; but were it found logically or experientially inadequate, it would soon be replaced.
Such cognitive behavior is in accord with the principle of induction, which allows us, and indeed enjoins us, to rely on the suggestions of appearance unless or until they are specifically shown to be illusory.
Had Descartes proceeded thus, in a more phenomenological manner than he did, he would not have given ab initio precedence to mind over matter, or alternatively to matter over mind, but he would have treated both domains as appearances of equal initial status to be later sorted out, and no dichotomy would have arisen in the first place. Descartes was in fact trying to proceed in a phenomenological manner; but his meditation did not begin far back enough.
Were it not for this natural, inductive approach, the opponents of Descartes would have a hard time explaining how come they manage to at all discuss both mind and body. How do those who believe only in the mind know about or understand claims to the body? How do those who believe only in the body know about or understand claims to the mind? Obviously, both groups start with the appearances of both body and mind, and it is due to this that they can communicate and debate.
The self. Moreover, to speak of a mind-body dichotomy is inaccurate and misleading in other respects. Our experience apparently covers three domains, not two. In addition to the physical phenomena we seem to outwardly perceive through the senses, and the mental phenomena we seem to inwardly perceive, which we call memories and imaginations (the latter being reshuffled memories), we believe in a third factor.
This is the self – that within us which perceives and thinks about the other two domains. This self – which we most identify with, rather than the mental and physical phenomena that surround it – is also experienced. It is known not merely by conceptual means, but primarily by a direct cognitive means we call intuition (or self-knowledge – i.e. knowledge of the self by the self).
The self (or soul or spirit) may be defined as that which is conscious in various ways, exercises will and makes value judgments. Such acts or functions of the self are also known by intuition. The difference between objects of intuition (i.e. the self and its functions) and all mental and material objects of perception is that the latter are phenomenal (they have phenomenal appearances like color, shape, sound, touch, smell, taste), whereas the former are non-phenomenal.
We do colloquially lump together the soul and its functions (spiritual appearances), mental phenomena (memories, imaginations – and derivatively, conceptual constructs), and some bodily phenomena (the nervous system, including the brain and all sensory and motor functions) – as “the mind” (or, I prefer to say: “the psyche”). But such unification is a simplification and should not be taken literally in the present context.
Indeed, if we go back to Descartes’ “I think, therefore I am” statement, we find in it three factors: “I” (the self), “think” (mental phenomena, supposedly observed by the self) and “am” (the inferred existence). Logically, the “being” inferred is just that of the self (and, though he does not say it, the mental phenomena of thought); but Descartes’ tacitly intended implication is that there is a physical substratum to such existence, i.e. a body and more broadly a physical world.
Anyway, this is how the argument is usually understood, as an inference of body and matter from self and thought (mind). The reason being that only such physical existence is regarded as ‘true’ existence, while mental and all the more so spiritual existence are regarded as a merely ‘virtual’ sorts of being. At least, this is the opinion implied by the proponents of a dichotomy between mind and body who have a materialist preference.
Those with more mentalist or spiritual propensities interpret the dichotomy as disproof of a material world. That is, they point out that Descartes’ premise (“I think”) does not logically imply any conclusion other than “I and my thought exist” – so that the usual inference that body and matter therefore exist is a non sequitur (it does not follow). Their error, of course, is to accept Descartes’ approach – whereas, as already shown above, the correct phenomenological procedure is not quite as he proposed.
Causality. As for the “law of causality” which some critics propose, that the domains of mind and body are so ‘substantially’ different that they cannot conceivably impinge on each other – this too is a figment of biased imagination. What do they base this alleged law of causality on? If we consider the concepts of causation (deterministic causality) and volition (causality through will), we find no basis for a ‘law’ that the substances of cause and effect must be the same. Such a law might conceivably be proposed as a hypothesis; but why do so, if such a hypothesis gives rise to intractable difficulties?
Causation can be formally defined with reference to terms of unspecified substance. For instance, the strongest form of causation between two items C and E can be defined as “if C, then E; and if not C, then not E”. Such a formal statement can be applied to any pair of items, even if one is mental and the other is material or vice versa. There is no justification refusing to apply the definition to cases where the terms refer to different substances.
With regard to volition, it is important to clarify the issues and not lump everything together. We can (in a first phase, at least) refer to our common sense beliefs for guidance, again on the basis of the earlier mentioned principle of induction.
These include that the self (soul) can will some mental events (e.g. some imaginations) and some material events (e.g. some physical movements of the body). It can do so (as introspectively evident) in its own mind and body – and also indirectly, in other minds and bodies (at least through its physical acts, if not in some cases through its mental acts).
Conversely, the self might be influenced in such mental or physical acts of will by mental and/or physical things of which it is conscious, or it might be causatively affected by such things (i.e. they might deterministically limit or widen its power to act).
An ‘influence’ functions through consciousness, and increases or decreases the ease or difficulty of a volitional act, but does not determine it; the act remains free, if the agent of it (the willing self) puts sufficient energy (will) into it. A ‘causative’, on the other hand, functions even if unbeknownst to the self, and does not affect the volition as such, but either delimits or enlarges its scope. All this is quite consistent, and no logical objection can be raised against it as an aetiological hypothesis.
Thus, in the direction from body to mind, we believe that mental objects (like sensations and memories) can arise from material causes; and that either (in some cases) through the influence of those objects when perceived or (in other cases) more directly through causation, the self’s acts of will and other aspects of behavior may be affected.
Conversely, in the direction from mind to body, we believe that the self has a power we call ‘will’ that can affect the body, either indirectly via events it produces in the mind that in turn causatively affect the body, or directly by producing changes in the body. Such effects of the will can in turn affect other bodies and minds.
We certainly have much introspective data on which to base these beliefs. These have the phenomenological status of appearances, i.e. the minimal credibility granted to all appearances initially. We are free, according to inductive logic, to use this database to build up a consistent intelligent theory of what is going on, provided we do not thereby create unsolvable problems.
Inversely, critics of this commonsense view of events must provide equally or more credible evidence and arguments in support of their contention. They must not only, as they tend to do, merely deny – but must also explain by what means and on what basis they are able to at all discuss the issue and take the intellectual positions they take.
Materialism. Now, there is one problem that some consider especially unsolvable. It is that the commonsense theory of a self, with consciousness and volition, interacting with a world of matter, is inconsistent with the exclusively materialist thesis that there is nothing but matter in the world and that matter can only move within a deterministic framework.
People who adhere to the latter thesis, who flatteringly call themselves scientists, are willing to accept indeterminism to some extent, in the sense that this is understood within quantum mechanics or in the Big Bang theory – but they refuse any possible impact of a non-material soul on material processes. That, to them, would imply a breach in the universality of modern physical laws.
This problem is easily solved. The solution is simply that all the so-called ‘laws’ of physics are known by inductive means – through generalizations or through theories based on adductive arguments. Such general propositions or ideas are undoubtedly based on empirical observations; but they also add to these observations, and such additions might well in time turn out to be unjustified by further observations. True scientific propositions are not exclusively empirical – they also depend on reasoning.
This being the case, it is absurd to argue that, since these ‘laws’ do not allow for non-physical things having any impact on physical things, any suggestion of volition is invalid. That is simply a circular argument – it begs the question. They do not prove in any way that spiritual entities (our self or soul) cannot affect (not even via mental events) physical events; they just assert that it is so.
It is not a conclusion of theirs; it is a premise. It is not a conclusion of any experimental or mathematical proof, but a prejudice (proposed so as to simplify the world for their simple minds). It is a modern dogma, as closed-minded as past religious dogmas that science was supposed to replace.
What is evident to any lucid observer and honest thinker is that the apparent universality of all these physical laws is made possible because their proponents do not address the introspective data at all. They ignore (i.e. discard, refuse to even consider) data that does not fit into their materialist way of looking at the world, and they call this ‘science’.
But science strictly means using stringent cognitive methodology: i.e. logic, inductive and deductive; it is not reserved to a materialist thesis. No such dogmatic reservation is philosophically ever justified or justifiable.
 I use the word ‘spiritual’ in a very simple sense, meaning ‘pertaining to the spirit’. Note also that the terms self, soul and spirit are to me identical – although some people believe in a self without a soul or spirit, namely Buddhists (on the one hand, who regard the self as ‘empty’) and Behaviorists (on the other hand, who identify the self entirely with the perceptible phenomena that most people consider as its mere effects).
 See my works The Logic of Causation and Volition and Allied Causal Concepts for detailed treatments of those concepts.
 I say ‘some’ mental and physical events, to stress that some (other) mental events are not caused by volition but by the brain (or whatever other means), and likewise for some (other) bodily events. The ‘mind’ and ‘body’ are domains affected by various causalities, and not by volition only or by causation only. There is no reserved domain either way.