Colin McGinn comments that "the idea of a peculiarly mental substance is, when you think about it, extremely weird: it is quite unclear that there is any intelligible conception associated with the words `immaterial substance'. This is shown in the fact that the alleged substance tends to get characterised purely negatively; it is simply a kind of substance that is not material. But we need some more positive description of what it is if we are to be convinced that we are speaking of anything comprehensible... We are prone,...to picture it in imagination as an especially ethereal or attenuated kind of matter, stuff of the rarefied sort we imagine...the bodies of ghosts to be made of--the kind of stuff through which a hand could pass without disturbance." (The Character of Mind, p. 23)

McGinn goes on in this passage to wonder whether "the immaterial substance is capable of discharging the role it was introduced to play," and whether it is only lack of clarity about immaterial substance that "induces us to suppose that locating mental phenomena in it is any advance on monism. The properties of the immaterial substance are supposed to constitute the nature of mental states: but what sorts of property are these? Here we seem faced with a dilemma: either we award the immaterial substance properties beyond the familiar mental properties, or we do not. If we do, thus conjecturing the existence of properties of mind hitherto undiscovered,...there will still be the question how these properties can constitute the essential nature of sensations and propositional attitudes. We cannot, without absurdity, postulate the existence of other conscious states which constitute the nature of the familiar ones; but it seems that nothing else can be the essence of our conscious states." (p. 24)

Earlier statements by McGinn in this same work are hard to reconcile with what he says here about the "familiar mental properties," and leave me, at least, somewhat uncertain as to where his real problem with mental or immaterial substance lies. Here he talks as if the problem were with what the "familiar mental properties" belong to or were found in, not with those properties themselves. In conformity with this he earlier said that "Consciousnesss, like redness or sweetness, belongs to that range of properties that can be grasped only by direct acquaintance." (p. 12) Concepts--such as sensation and belief--that apply to consciousness "can be grasped only through acquaintance with what they are concepts of," and hence are, in his terms, ineffable. But then he goes on to say some very remarkable things, in this earlier passage: namely, that "consciousness is elusive even to acquaintance, as an exercise in introspection will reveal. Consider you consciousness of some item--an external object, your own body, a sensation--and try to focus attention on that relation: as many philosophers have observed, this relation of consciousness to its objects is peculiarly impalpable and diaphanous--all you come across in introspection are the objects of consciousness, not consciousness itself. This feature of consciousness has induced some thinkers to describe consciousness as a kind of inner emptiness; it is nothing per se but a pure directedness on to things other than itself. No wonder then that it is hard to say what consciousness intrinsically is." (pp. 12-13)

I have quoted at length from McGinn because I think he gets out in a rather neat fashion many of the commonplaces about the mind or soul and how it presents itself that have framed the philosophy of mind and self since the 18th Century or before.

Descartes says what he is and replies to objection that we have no image of the self.

Locke surrenders possibility of knowledge of substance because we have no idea of substance itself, but only of a "whatever" that gathers qualities together.

Hume draws the consequences of the Lockean epistemology and makes the famous statement that that: "When I turn my reflexion on myself, I never can perceive this self without some one or more perceptions; nor can I ever perceive any thing but the perceptions. 'Tis the composition of these, therefore, which forms the self." He continues to say that "Philosophers begin to be reconcil'd to the principle, that we have no idea of external substance, distinct from the ideas of particular qualities. This must pave the way for a like principle with regard to the mind, that we have no notion of it, distinct from the particular perceptions." (Appendix to his Treatise of Human Nature, pp. 634f of the Selby-Bigge edition) In the chapter, "Of Personal Identity," in Book I of the Treatise he compared the mind to a theatre, "where several perceptions successively make their appearance, pass, re-pass, glide away, and mingle in an infinite variety of postures and situations." Then he adds: "The comparison of the theatre must not mislead us. They are the successive perceptions only, that constitute the mind; nor have we the most distant notion of the place, where these scenes are represented, or the materials, of which it is compos'd." (p. 253)

Kant's section on the "Paralogisms" in the 1st Critique.

Comte's insistence on the impossibility of grasping our mental acts by reflection: "like a hand striking itself."

G. E. Moore's statements, in "The Refutation of Idealism" (Mind, 1903), that in a sensation of blue "the term `blue' is easy enough to distinguish, but the other element which I have called `consciousness'--that which sensation of blue has in common with sensation of green--is extremely difficult to fix. That many people fail to distinguish it at all is sufficiently shown by the fact that there are materialists. <Reeeeeaaaly!> And, in general, that which makes the sensation of blue a mental fact seems to escape us: it seems, if I may use a metaphor, to be transparent--we look through it and see nothing but the blue; we may be convinced that there is something but what it is not philosopher, I think, has yet clearly recognised." (p. 20 of his Philosophical Studies)

And again Moore says (p. 25): "The moment we try to fix our attention upon consciousness and to see what, distinctly, it is, it seems to vanish: it seems as if we had before us a mere emptiness. When we try to introspect the sensation of blue, all we can see is the blue: th other element is as if it were diaphanous. Yet it can be distinguished if we look attentively enough, and if we know that there is something to look for. My main object in this paragraph has been to try to make the reader see it; but I fear I shall have succeeded very ill."

And again Moore says (p. 26): "Introspection does enable me to decide that...I am aware of blue...., that my awareness...has to blue the simple and unique relation the existence of which alone justifies us in distinguishing knowledge of a thing from the thing known, indeed in distinguishing mind from matter." And: "The relation of a sensation to its object is certainly the same as that of any other instance of experience to its object." (p. 28) This is the general relation of intentionality or reference, no doubt.

So McGinn's statements stand in a long tradition--perhaps a long tradition of confusion. Certainly it is hard to make sense of all that McGinn says. He moves from the claim that the relation of consciousness to its object is "peculiarly impalpable and diaphanous" to the claim that "all you come across in introspection are the objects of consciousnes, not consciousness itself," and here by "consciousness itself" he clearly is not refering to the substance of consciousness but "familiar mental properties." But if that's all you come across, then you could not know that you were introspecting--since you are only conscious of objects of consciousness--and you would not know that consciousness is impalpable and diaphanous. And you would not know it is a "pure directedness on to things other than itself" (as J.-P. Sartre says: Trying to catch a bus, e.g.) And if it is pure directedness, then that is, precisely, a determinate nature and not an "inner emptiness" at all. And if that is true one wonders why--beyond general problems of substance and quality that afflict the physical as well as the mental--these determinate natures could not come together to form substances quite as well as the determinate natures that enter into physical objects do. Ultimately, of course, everything is "weird." That is a part of what it means to be ultimate.

Over against the idea that subjectivity or the mental or soulish is an emptiness stands our de facto awareness of our own mental or experiential states. When someone asks us how we feel, we can tell them in great detail. When the Optometrist asks us to look through the lenses and read the letters or report on other aspects of our visual experience, we do so promptly and accurately. There is nothing vacuous at all about what we report on. Motivational psychologists, actors, novelists, poets, interior decorators and cooks constantly report on and describe the subjective flood of mental life that makes up our existence. The idea of "inner emptiness" is a ridiculous contrivance of a view of mind based on the mythology of empiricism.

One finds this inner flood, instead of emptiness, dealt with rather well in Wm. James Principles of Psychology, Chapters IX and X--"The Stream of Thought" and "The Consciousness of Self" respectively--though James also will have nothing to do with the soul as a substance. Chapters XVII-XXVI cover particular segments of the mental flood, from sensation to reasoning, from emotions to will, etc. etc. Edmund Husserl treats "the pure psychical being or the psychical life...as a nature-resembling flow of events in a quasi-space of consciousness" ("Author's Preface to the English Edition," hardback ed. p. 24) Here in the nature `transcending' sphere we have an "infinitude of knowledge previous to all deduction" (p. 12) or theorizing, "an absolutely independent realm of direct experience, although for reasons of an essential kind it has so far remained inaccessibe." (p. 11) In Being and Nothingness, J.-P. Sartre takes 900 pages of turgid French to describe that `nothing' that is the life of the mind. John Searle states that it is an obvious fact about our own experience that "we are all conscious and that our conscious states have quite specific irreducible phenomenological properties." (Rediscovery of the Mind, p. 28) And: "Beliefs and desires are experienced as such, and they are certainly not `postulated' to explain behavior, because they are not postulated at all." (p. 61) He emphasizes throughout his book "the enormous variety of our consciousness life" (p. 227), which we "experience as such," though not "incorrigibly" or by some special faculty of "introspection."

The "inner emptiness" line cannot account for what we actually know about the flow of reality that makes up our own lives. Empiricism as a theory of knowledge is a recognized failure in any form that has been definitely specified, and has nothing left to support it but the bias of a sensualistic culture. There is no reason to regard conclusions about mind or substance that derive from it as serious challenges to what the ordinary, thoughtful and experienced person assumes to be the case about self-knowledge and self-identity. Anything that we can accurately report about our experience must be assumed to be the case, and there are a huge number of things of various general types that any individual can accurately report about their own minds and experience. It is these accurately reportable events and structures that make up the texture of the human mind and soul and reveal its substance.