I saw a crowd stand talking
I just came up in time
Was teaching the lawyers and the doctors
That a man ain't nothing but his mind
Blind Willie Johnson
Way back about two thousand three hundred years ago Aristotle wrote a book called "On the Soul". This book is hard to read nowadays and some of the allusions within it are now unclear but it is still the definitive work on philosophy of mind.
It is definitive because it describes two key concepts of the philosophy of mind. The first key concept is the "regress":
"Since it is through sense that we are aware that we are seeing or hearing, it must be either by sight that we are aware of seeing, or by some sense other than sight. But the sense that gives us this new sensation must perceive both sight and its object, viz. colour: so that either (1) there will be two senses both percipient of the same sensible object, or (2) the sense must be percipient of itself. Further, even if the sense which perceives sight were different from sight, we must either fall into an infinite regress, or we must somewhere assume a sense which is aware of itself. If so, we ought to do this in the first case. " (Book 3, part 2
When budding materialists come across this concept they think "you cant see yourself seeing or you will get in an endless cycle so what we call consciousness or mind cant exist!". Every Direct/Naive Realist from la Mettrie to Dennett has this argument in mind. But notice how Aristotle deals with the problem: "we must either fall into an infinite regress, or we must somewhere assume a sense which is aware of itself". Aristotle does not fall straight into the trap of assuming that the infinite regress argument is the only possibility, it could also be assumed that a sense might be self aware. (See The symbol grounding problem and Chinese Room for a modern insight into the regress).
Aristotle considers self awareness in depth in "On the Soul" and ultimately discovers that it is linked to our idea of time. This leads Aristotle to consider the second key concept: how time is involved in mind. The text describing this second concept has probably been obscured over the ages because most medieval copyists would have found it incomprehensible. Despite this, Aristotle's idea of time and mind is still worth considering:
"The answer is that just as what is called a 'point' is, as being at once one and two, properly said to be divisible, so here, that which discriminates is qua undivided one, and active in a single moment of time, while so far forth as it is divisible it twice over uses the same dot at one and the same time. So far forth then as it takes the limit as two' it discriminates two separate objects with what in a sense is divided: while so far as it takes it as one, it does so with what is one and occupies in its activity a single moment of time."
This is complicated unless you realise that he is saying that in the same way as two spatially separated objects can project geometrically at a point so can two temporally separated objects. In this analysis he is envisaging time as a dimension with events laid out as they are in space.
Aristotle clarifies this:
"But that which mind thinks and the time in which it thinks are in this case divisible only incidentally and not as such. For in them too there is something indivisible (though, it may be, not isolable) which gives unity to the time and the whole of length; and this is found equally in every continuum whether temporal or spatial."
Materialists generally oppose this, relativistic, concept of time to preserve their interpretation of the regress argument. But in truth the dimensionality of time is well established (see Special Relativity ebook). In modern terminology Aristotle is arguing that for mind a space-time interval can truly be a zero distance (cf: this happens for photons).
Those who are irked by the idea of time as an existent direction for arranging things might care to look at the latest work on attosecond laser pulses. Using these pulses it is possible to get an electron to interfere with its own, historical self, creating a double slit experiment in time. (See Lindner et al. (2005). Attosecond double slit experiment. and Horwitz's analysis of these experiments).
So why do materialists continue with the assertion that you cant possibly perceive a perception because this would cause a regress when Aristotle told them millennia ago that extension in time would resolve the problem? Whitehead has the answer in his Concept of Nature: Time:
"The eighteenth and nineteenth centuries accepted as their natural philosophy a certain circle of concepts which were as rigid and definite as those of the philosophy of the middle ages, and were accepted with as little critical research. I will call this natural philosophy 'materialism.' Not only were men of science materialists, but also adherents of all schools of philosophy. The idealists only differed from the philosophic materialists on question of the alignment of nature in reference to mind. But no one had any doubt that the philosophy of nature considered in itself was of the type which I have called materialism. It is the philosophy which I have already examined in my two lectures of this course preceding the present one. It can be summarised as the belief that nature is an aggregate of material and that this material exists in some sense at each successive member of a one-dimensional series of extensionless instants of time. Furthermore the mutual relations of the material entities at each instant formed these entities into a spatial configuration in an unbounded space. It would seem that space---on this theory-would be as instantaneous as the instants, and that some explanation is required of the relations between the successive instantaneous spaces. The materialistic theory is however silent on this point; and the succession of instantaneous spaces is tacitly combined into one persistent space. This theory is a purely intellectual rendering of experience which has had the luck to get itself formulated at the dawn of scientific thought. It has dominated the language and the imagination of science since science flourished in Alexandria, with the result that it is now hardly possible to speak without appearing to assume its immediate obviousness."
And still, a century after Whitehead, the materialists are dominant in philosophy, and yes, to their shame, in science. In the twenty first century it is known that Alexandrian cosmology is incorrect and it has even been experimentally demonstrated that dimensional time exists. It is crucial that philosophers and scientists re-evaluate their theories in the context of modern cosmology and do not take the lazy option of believing that a "Newtonian approximation" is a valid approach to how events are arranged in space and time. In fact the entire story of the philosophy of mind is a tale of how Alexandrian cosmology cannot explain our experience. Our experience, like the world itself, is not composed of isolated, frozen 3D structures that succeed each other in time and the philosophy of mind in the last hundred years amounts to little more than twenty different ways of stating this fact. In a feat of jaw-dropping hubris and contrary to the spirit of scientific endeavour, the conclusion that is drawn from this failure is often that Alexandrian cosmology must be correct and the mind does not exist!
Incidently, Aristotle, by a quirk of the fate of ideas, was probably partly responsible for the rise in materialism because he portrayed time as the same everywhere in his "Physics" .