In this chapter, I want to specify some of the logical preconditions for
any theory of knowledge. Some such criteria have of course been developed
throughout the present treatise, here my concern is with issues relating to the
role of the nervous system.

The intent is not to present a complete and definitive model of
knowledge, but merely to demonstrate how a theory of cognition and memory must
be tailored around certain fundamental insights of logic. Proposals falling
short of these specifications may be rejected at the outset as without

The Immediacy of Sense-Perception.

Logical Conditions of Recognition.

Other Applications.


The Immediacy of Sense-Perception.

There is a very important first principle for all philosophy, all
ontology, all epistemology, all science, supplied to us by logic. It is that we
cannot consistently deny the ultimate objectivity of (some) knowledge
We cannot logically accept a theory of knowledge which in effect invalidates
knowledge. (I personally learned this insight from Ayn Rand, though I seem to
recall that she attributed it to Aristotle, in spirit at least.)

This means that the currently popular view that
sense-perception is no more than a production of mental images — is logically
. Such a statement
might at first sight seem ridiculous, since it denies something universally
accepted as common sense, not only by most lay people, but even by some major
philosophers and many scientists; however, bear with me, and we shall see its

Ask anyone to express the work performed by our senses, and they are
likely to reply: ‘light or sound or whatever impinges upon the corresponding
sense-organ, and produces an electrochemical message, which is transmitted to
the brain, where it is somehow translated into a mental image — which is what
we in fact perceive in sense-perception (rather than the external physical
phenomenon itself)’. To evaluate that position, we must make a distinction
between its descriptive and interpretative aspects.

The description is given us by common experience and research by
biologists. Sense-organs (from sense receptors to brain centers) play some
crucial role in perception, since if they are blocked or damaged it is affected,
and they have such and such a physiological configuration and manner of
functioning. That is the empirically evident data underlying the above
statement, and I am not contesting it.

On the other hand, the interpretative element is the belief that what we
perceive, at the tail end of the described processes, are ‘mental images’,
psychological phenomena which hopefully ‘resemble’ the original physical
phenomena, produced in the brain somehow. This is a theory, which is open to
question on purely logical grounds: if all what we perceive are ‘mental images’,
then how can we know that these are images of
anything, and even if they are, how can we know they in any way resemble
their physical causes?

More specifically, our descriptive knowledge of the sense-organs and
their processes, becomes no longer empirical but a mere postulate, which
therefore cannot be used to confirm the theory. If our apparent perception of
our body and the physical surrounds may itself only be a day-dream, as the
theory suggests, it cannot be used as empirical evidence that there is a body
surrounded by a physical world which together produce mental images.

Thus, though the theory in question begins with a presumption that there
is a material world (including the sense-organs and external stimuli), it ends
with a possibly contradictory logical conclusion that there may well not be such
a world, precisely because our
knowledge of it is mediated by the senses. On the one hand, it views its data on
the pathways of sensory messages as physical
evidence for itself; on the other hand, it goes on to possibly deny the reality
of such physical evidence.

Had we not begun with a presumption that there is a material world
(radically distinct somehow from the immediately knowable mental world), there
would have been no need to construct a theory relating certain perceptions to
the sense-organs. All objects, whether mental or physical, including the sense
organs, would be of the same, essentially fantasmic, stuff — and thus all
equally directly knowable.

An issue only arises when we take for granted the common sense view that
there is a physical (as against mental) world, from which the perceiver is
separated by a body with sense-organs. This view is credible, since mental and
physical phenomena do experientially seem to us somehow substantially different.
It follows that the theory in question intrinsically presupposes (logically
implies) that the descriptive data is specifically physical.

We thus have two modal hypothetical propositions in contradiction: ‘if
the theory, then the data may not-be physical’ and ‘if the theory, then the data
had-to be physical’. The antinomy involved is not of the form ‘if P, then nonP’,
but of the form ‘if P, then both ‘possibly not Q and necessarily Q’, which
implies ‘possibly {nonQ and Q}’. A theory which denies its own starting point
has no logical standing.

The objects of sense-perceptions cannot be claimed to be mental images of
otherwise inaccessible physical phenomena: because, if they are inaccessible,
how can the proponents of that theory claim to have access to them and know anything about them?

They cannot logically lay claim to any underlying physical events; and
even if they do, what guarantee have they that the mental images perceived have
any resemblance whatsoever to any
presumed physical causes? An effect need not resemble its cause. Thus, it may
well be that, say, the mental image of ‘green’ is invariably caused in
everyone’s mind by a physical event of ‘square’: no one could tell. No claim of
‘truth’ could be made by anyone — not even by the proponents of that theory
(it is intrinsically unconfirmable).

But in any case, there would be no justification in regarding perception
of ‘externally generated’ mental images as in any wise more mysterious than
perception of ‘inwardly produced’ mental images: all phenomena would have the
same status. The subjectivity theory constructs redundant ‘duplications’, with
the group of mental phenomena labeled ‘physical’ needing repetition as mental
phenomena labeled ‘nonphysical’.

The problem has baffled philosophers, but I do not see why. If a position
leads to paradox, logic demands that we simply reject it and find another. Here,
although it is obvious that the apparent sense organs indeed
must play a significant role of some sort
in physical perceptions (since
without them, it is lacking), the initial assumption that this role is
production of mental images turns out to be inconsistent. Ergo, that assumption
is nonsense, and some other explanation of the function of these organs must be

To resolve the paradox, while maintaining that the data is indeed
physical, we are logically forced to conclude that sense-perception (no matter
what many people believe), is a direct,
relation of consciousness, between the physical objects and the
perceiver. We must accept that when we perceive an external object, it
is the object itself and not some ‘representation’ of it that we in fact
. We must from the outset admit the objectivity of sense-perception.

We must accept this primary logical requirement, and build our theory of
knowledge around it. There is no escape from the logic. Thus, the light from a
material object, its activity in the retina of the eye, the messages sent on to
the brain — all these physically evident intermediaries of sight must be
regarded as mere causal preliminaries, preparing us somehow for the actual act
of seeing, which however is an unhindered Subject-Object relation. Likewise for
the other senses.

(The computer provides us with an interesting analogy, though a partial
one. The Subject keys in a statement he is reading on his table. The keyboard
and CPU/Disk of the machine represent the sense-receptors and brain; the changes
produced in the machine correspond to the nervous impulses and imprints; the
partial display on-screen are analogous to mental images. But note well that the
Subject sees both the external object and the on-screen copy if any, and is not
himself to be confused with the machine.)

Philosophy is still left with the task of proposing alternative
explanations for the role of the sense organs and their processes in physical
perception. Starting with the admission of the common-sense view that there are
physical, as distinct from mental, phenomena (including our bodies), manifold
functions may be suggested offhand:

Some have recently suggested that the senses may serve to filter out impressions other
the ones focused upon. It may well be that the senses produce a
preliminary, relatively rough, mental image which allows us to decide whether we
are sufficiently interested in the underlying object to awaken and invest a
further effort of (more direct) consciousness towards it. Indeed, analysis of
sensory messages seems to indicate that their content is relatively skeletal.

Perhaps the sense organs serve to somehow pin-point a consciousness which
would otherwise be too general. It may be that the awareness of a disembodied
soul would be too dilute to be effective in this world, like the state of mind
called ‘enlightenment’ pursued by mystics. The senses may provide a material
framework, a set of physiological conditions, in which an adequate ‘line of
relation’ between perceiver and physical percept can be established, a ‘pipe’
though which a ray of consciousness can be sufficiently intensified.

It also seems likely that mental images are indeed simultaneously
produced by sensory messages (always or often, automatically or by choice), as
an incidental side-benefit, for purposes of future recall
. Whether the
sensory-messages produce both the nervous-imprint and the mental image, or (less
likely) it is the actual perception which produces the mental image,
independently of the nervous-imprint, I do not know.

These are just suggestions which come to mind; there may be better
explanations. But in any case, the suggestion that the function of the senses is
exclusively the production of mental images, which are all that we perceive, is
logically unacceptable, and therefore wrong without a doubt.

Whatever the biological processes involved, then, at the moment of
sensory perception (and, it seems to me, lingering on for a brief time
thereafter, at least in some cases), the perception is direct. That the physical
perception is thus direct, does not guarantee that it is complete, nor that it
is pure of additional projections of an interpretative nature, note well. But if
we are properly attentive, we can focus on the given exclusively.

An image may indeed incidentally be formed in the brain, for purposes of
preliminary filtering and/or future recall. Such an image may be a clear and
faithful mental ‘photograph’ (or ‘audiograph’ or whatever, as appropriate), or a
vague and distortive one, but the initial perception relates to the object
itself, not this image. This, to repeat, is a logical necessity.

It may be that we have some difficulty in accepting sensory perception as
direct, because we tend nowadays to regard the soul as localized ‘in the head’,
contiguous with the brain. This creates a physical distance
between the perceiver and the things perceived, which are located at the other
extremities of the sense organs. But it may well be that the soul is more
extended than we assume, permeating the whole body; in that case, the issue of
distance would be resolved.

With regard to introspective perceptions, they are generally of course
accepted without question as irreducible primaries. This refers to concrete
mental phenomena which are not, at the time they arise, stimulated by sensory
stimuli, though they may well in the past have been, wholly or partly, given
initial existence and form by sensory stimuli.


Logical Conditions of Recognition.

But the main function of the nervous impulses generated by sensation (and
similarly for nervous impulses underlying intimate perception), is production of
biological imprints which are necessary to recognition.
Not mental images, note well, but codes of a physical (meaning nonmental)
nature in the cells of the brain.

When we perceive two objects at the
same time
, we can immediately ‘see’ (in the largest sense of intuitive
insight) that they are ‘similar’ or ‘different’ in various respects. These
direct comparisons may not at once reveal all the similarities and differences,
and some of them may later be disagreed with and judged illusory — but in any
case, these acts of consciousness are the primary building blocks of what we
call ‘conception’.

Comparing simultaneous percepts seems simple enough, but what of
comparison of percepts which are separated
by time
? It is hard to say that in such case we ‘evoke’ a mental image of
the past percept and match it with the present percept, because introspection
shows that in most cases we are able to construct only a very imperfect analogue
of the initial impression, if any.

Indeed, even as we call the image up, we know the image itself
to be (usually) only a rough copy of the original direct percept, which implies
that we are able to compare the present mental image to the past object by some
means other than with reference to a
mental image. In other words, the image itself is liable to some judgment
regarding its correctness.

It follows that our decision as to whether the perceptual object now
facing us is or is not the same as some past manifestation, is not (or not
exclusively) made through the intermediary of a stored mental image. How, then,
are we able to ‘recognize’ anything, how can we claim that we have seen anything

This is a logical problem, as well as a more broadly epistemological one,
in that logical science is based on the assumption that similarities and
differences are recognizable across time.

Our goal here is not to debunk human knowledge, for as we have seen such
a reaction is logically untenable. Our goal is more humbly to determine the
logical conditions for objectivity of knowledge. That knowledge is objective is
indubitable, since the premise of subjectivity is self-contradictory. Two
solutions to the problem may be proposed.

One, is to suppose that direct perception of past concrete objects is
feasible; that long after an event is over, we may transcend time and space
somehow, and sometimes ‘see’ it, the past event itself (not its present
repetition or continuation), extra-sensorily. But this solution seems very
far-fetched, even though not impossible to conceive. I have made attempts in
that direction, but they are too speculative to include here.

Two, is to suppose that the distinguishable components of each concrete
object (whether physical or mental) we perceive produce a certain ‘nervous
(let us call it) in the brain, which is substantially a physical
(rather than mental) phenomenon of some sort. Such an ‘imprint’ may be a certain
electrochemistry of the nervous cells — a molecular arrangement, a location or
orientation of certain molecules, a specific combination of electrical charges
— perhaps including a distinct synaptic network; whatever it is (it is for
biologists to determine just what), we here predict it on logical grounds.

Thus, what happens in recognition is not comparison of the new percept, to the
mental image of the old percept, but comparison of the nervous imprint of the
new percept, to the nervous imprint of the old percept.
If they match
perfectly, the objects ‘seem’ identical; to the extent that the nervous imprints
do not entirely fit each other, the objects are ‘experienced as’ dissimilar.
This idea admits that not only sense-percepts produce imprints, but even mental
images we construct voluntarily or otherwise may do so, note well.

In this way, even the mental image of an old percept can be judged as
rough or accurate, according to whether the nervous imprint of the image is in
all respects the same or only partly so, to the nervous imprint of the object it
claims to reproduce. We may well suppose that the mental image is often a
projection caused by the nervous imprint; this would explain why images which we
normally find difficulty evoking clearly at will, may suddenly appear with force
in dreams or under the influence of drugs, say.

The ‘matching’ of nervous imprints should not be viewed as a conscious
comparison, but rather as a subliminal
process whose end-product is a signal, directly perceived or intuited by the
conscious Subject, that the objects in question, be they physical or mental
phenomena, match to a greater or lesser degree. Note well, it is not the
imprints themselves that we ‘see’, but some signal from them. Uncertainties may
be explained by supposing that nervous imprints sometimes decay, or are lost;
likewise, distorted memories may be due to deterioration of imprints.

In this way, past and present physical and/or mental objects are
comparable. This theory frees us of the problems associated with the idea that
mental images are the intermediaries of recognition across time. However, it
contains logical difficulties of its own! What guarantee is there that an old
nervous imprint has not been distorted, so that we ‘recognize’ a new object
which is in fact unlike the old, or fail to ‘recognize’ a new object which is in
fact like the old?

The only solution I can think of is ‘holistic’. To claim that such
confusions invariably occur would be logically inconsistent, since such a
statement (again) would be invalidating itself. Therefore, logic demands that at
least some such comparisons have to be admitted to be correct. The question of
‘which?’ can only be answered by a broad consideration of all experience and
logical insight.

That is, over time, if such errors have crept in, inconsistencies will
eventually arise, which will signal to us that something, somewhere, went wrong,
and we will accordingly modify our outlook in an attempt to resolve the
contradictions. In other words, the experiences of similarity or difference are
phenomenal, and are taken at face value until and unless otherwise proven, like
all other experiences.


Other Applications.

Once we come to the realization that perception of physical objects
(sensory perception) logically has to be as direct as perception of mental
objects (intimate perception), it is much easier to accept the statement made in
the previous chapter that conceptual insight also may be a direct Subject-Object
relation, when its object is external as well as when its object is internal.
Such immediate conception has been called intuition, in contrast to reflective

The only difference between perception and conception is that the former
is directed at concrete objects, and the latter at abstract objects. The only
difference between sensory and intimate perception is that the former is
directed at physical objects, and the latter at mental objects. A similar
division can be made with regard to conceptual insight, whether intuitive or
reflective, by reference to the physicality or mentality of the objects
concerned. But in all these cases, the consciousness relation is one and the
same phenomenon.

In conclusion, physical as well as mental concretes, as well as certain
intuited abstracts, may be known directly and immediately. These, whether rooted
in externally or internally directed acts of consciousness, serve as the raw
givens of knowledge, and are in themselves
indubitable. However, beyond these ‘received’ primaries, most knowledge is
constructive, and open to doubt and review.

By ‘constructive’ is meant, that concrete or abstract mental images may
be reshuffled in any number of ways, forming innovative, hypothetical entities.
The ‘building-blocks’ of such imagination are given from previous, ‘received’
concrete or abstract experiences; but these may be separated from each other and
combined again together in new ways. Such fictions are often effected by
manipulation of allied words (see ch. 4), but they may also be made wordlessly.

These constructs are to begin with imaginary, but some of them may
eventually be supposed, with varying degrees of logical probability, to have
equivalents which are not imaginary. Inductive work is of course required to
confirm such suppositions. Fictions are of course not always deliberate
imaginings for research purposes; they may be unintentional misperceptions or
misconceptions, or only intended for entertainment or more obscure ends.

It should be obvious that what has in this text been referred to as a
‘nervous imprint’, is simply one of the senses of the word ‘memory’. I avoided
that word, because it is variously used, also in senses which suggest renewed
consciousness, or the reviewed objects, or actual images of previous objects —
whereas I wanted to stress the subliminal aspect of memory, its material

Now, let us consider recognition more broadly. We suggested that when a
percept (a concrete object of perception) is recognized, each of its many
concrete attributes is encoded in the brain in some way, and matched against
previous such nervous imprints.

Thus, there is supposedly a peculiar code for ‘red’, another for ‘hot’,
and so forth, as well as for the various measures or degrees of such
characteristics. We may similarly suppose that there is a special code for each
of an object’s abstract attributes — that is, for each concept (abstract
object of conception).

You may remember, we distinguished between two kinds of imagination:
‘perceptualization’, the projection of any concrete mental image, and
‘conceptualization’, the projection any abstract mental image. Whether such
projections are voluntary or not, their recognition is effected in the same way.

Note well also that a mental image, whether concrete or abstract, may be
recognized as resembling a physical phenomenon, in any respect other than the
substantial one (obviously they will remain differentiated as mental and
physical, respectively).

However, concrete and abstract phenomena, whatever their substance,
cannot be equated to each other, though they may of course be in some way
causally associated. In practise, of course, almost everything we consider is a
mix of concrete and abstract components, so some comparison usually does occur.

Thus, recognition, in its widest sense, concerns any kind of object.
Anything distinguishable in some way, be it physical or mental, concrete or
abstract, is supposedly recognizable. Thus, recognition is ultimately
recognition of what we call ‘universals’, the various components of things,
which bundle together into what we call ‘particulars’ (more precisely, we mean

That is not to say that there is nothing more to a ‘universal’ than a
distinct code, for the codes themselves are in fact just ‘individuals’ — but
it is merely an observation as to what we may reasonably expect the nervous
imprints, which we earlier posited, to correspond to. The point is that there is
no essential difference between recognition of concretes and abstracts, be they
physical or mental, however they were generated.