Superphysics Superphysics
Section 9

The Proofs of the Essentiality of the Soul, and of Its Independence of Body

by Avicenna
11 minutes  • 2137 words
Table of contents


One of the logical proofs for establishing this Claim requires premisses, among which are:

Premise 1

Man conceives universal (generic) notions wherein a greater or less multitude participates, such as man at large, and animal at large.

And of these generic notions there are such as he conceives through a particular [or partial, or an obligatory] synthesis, and there are such others of these generic notions as he does not conceive by any synthesis, but singly and individually. And unless he shall have conceived the latter division (class, sett), it is not possible for him to conceive the former.

Further, he conceives each one of these generic universal notions only under one form, wholly stripped[Pg 80] (abstracted) from all relationship to its concrete sensuous particulars, since the particulars of each one of the generic notions are potentially endless [in variety and number] and no one of the particulars has any right of priority over another particular in respect of that one form of the generic notion.

Premise 2

A form, whatsoever body it detaches, reduces, and adorns, and in general whatsoever individual of divisible things it so takes hold of, it clothes the same and exactly fits the same in every one of its parts. And whatsoever clothes and exactly fits a divisible thing in all its parts is itself divisible; and hence every form that has clothed and exactly fitted any body whatsoever is itself divisible.

Premise 3

In every generic (universal) form, if regard be had, in the division of such form, purely and simply to its abstract self, then it will not at all validly follow that the parts into which it has been divided shall necessarily resemble the whole in its complete notion; otherwise it must follow that the generic form, whose division has been made in respect of its abstract self, has not been itself divided, but that it has been divided into its constituents, whether these be its various species or its numerous individuals, whereas multiplicity of species or of individuals does not necessarily entail division in the abstract generic notion itself.

But such division has actually taken place, which is a contradiction.

Hence our assertion that the parts of the generic form do not resemble it in its full and complete notion is a true dictum.

Premise 4

that in the mental form, if regard be had to its division, it will not validly follow that its parts are denuded (stripped) of the totality of its notion.

This is because, if we admit such total denudation, and assert that these parts are utterly aloof from the complete conception of the generic whole, then the form will arise, in such parts, only upon their assembling together, so that they are in fact things devoid of that form which will arise in them on their being set together, which is a quality of the parts of materia capax or passive matter which occupies space ([Greek: dektikon: δεκτικον]);

[Note: The recipient is the acted upon, and it is called matter, and also place.]; and hence the division has not been effected in the generic form, but in its objective concrete materials. But it has been asserted that the division has come to pass in it: this too is a contradiction. Therefore our assertion: “It will not validly follow that its parts are stripped of the totality of its notion” is a true statement.

Premise 5

This is the result of Premise 3-4

In the generic form, if it be possible that divisibility be considered in it, then[Pg 82] its parts are neither wholly devoid of the perfect form nor are completely exhaustive of it, and are as it were [component, constituent] parts of its definition and outline (or description).

Given then these premisses, we shall further unquestionably say that a mentally-grasped form—in short all knowledge—claims some abode somewhere, which abode is both an essence itself and a part of man’s self, so that such essence will not be devoid of being either a divisible (material) body or a non-corporeal indivisible essence.

I however say, that it is not licit that it be a corporeal body; because a generic mentally-grasped form, if it abide in a body, then it is inevitably possible for divisibility to befall it, as we have shown above.

Nor is it licit that its parts be otherwise than resembling the whole from one standpoint, and contrasting with it from another standpoint, in a word each one of the parts contains somewhat of the notion of the whole; whereas there is no generic form whatsoever but of whose parts a compound can be formed that is partly like it and partly unlike it save genera and differentia; consequently these parts are genera and differentia, and hence each one of them is in its turn a generic form; and thus the same assertion repeats itself as above.

Inevitably this will end in a form that is no longer divisible into genera and differentia,[Pg 83] owing to the impracticability of progression ad infinitum into parts differing in notions, even if it be established that corporeal bodies are so divided into parts ad infinitum.

Moreover it is well-known that the generic (universal) form, concerning which it is held that it is divisible only into genera and differentia, if there be nevertheless some of these two that is not divisible into genera and differentia, then this some will be in itself utterly indivisible in every sense and respect; and consequently what is compounded, of these two of that some, will also be indivisible, seeing that it is well-known, for example, that man cannot be conceived except along with the two conceptions living and rational (speaking).

In short, it is not possible to conceive a generic universal form that has genus and differens save by conceiving them all together. Therefore, the form which we have described as having taken up its abode in the body has not taken up its abode therein, which is a contradiction, and therefore the diametrically contrary to it is true, namely our assertion that a generic (universal) mental form does not abide in any corporeal body whatsoever; and consequently the essence in which a generic mental form abides is a spiritual essence, not qualified with the qualities of bodies, which is what we call the Rational Speaking Soul. And this is what we set out to show.


A second of the proofs, which corroborate this claim and confirm (correct) it, is what I am now going to set forth. I say then that body of and through itself does not effect conception of mentally-grasped things, since all bodies have in common that they are body, and differ amongst each other in capacity for conceiving mentally-grasped things. Wherefore living (animal) bodies are qualified to conceive mentally-grasped things only by and through certain powers that are put within them. And if these powers conceive by and through themselves, without the cooperation of the body, it follows that they are in themselves fit and apt to be an abode for mental forms. And what is thus qualified is itself an essence; consequently if such conception is occurring, they, namely these powers, are essences.

This power conceives mentally-grasped things by and through itself only, and not at all through cooperation of body; for, we contend, concerning whatsoever perceives any thing through cooperation of body, that the oftener wearying perceptibles are repeated upon it the more do they tend towards ruining and spoiling it and producing dullness and exhaustion in it, it being nothing but a frail instrument and organ whose strength has been reduced, owing to the over-tasking imposed upon it on the power’s employing it.

This cause the seeing power, for example,[Pg 85] gets weaker the oftener it persists in looking at the sun’s shape. So too the hearing power, if loud sounds reach it repeatedly.

Whereas this power, to wit the one that conceives mentally-grasped things, the more it perceives wearying mental conceptions the stronger it becomes for its work [the more efficient it becomes], wherefore it has no need for an instrument in its operation of perceiving, and hence it perceives of itself. Now, we have already shown that every power perceiving of its own self is an essence; so then this power is an essence, which is what we set out to show.


Among the proofs that guide to this claim is what I shall now show, so I say as follows.

The indwelling (immanence) of form in body is at once both passive and receptive—passivity of the form and receptivity of the body. And whereas one and the same thing excludes the possibility of its being both doer and done, it becomes clear unto us that a body is not able of itself to dress itself in one mentally-grasped form and strip off another. Yet nevertheless we see a man consciously and with forethought conceiving and proceeding from one mentally-grasped form unto another, which operation is not devoid of being either an act peculiar to body, or else an act peculiar to the rational speaking power, or finally an act commonly shared between them[Pg 86] both.

Section 2 showed that it is not licit to attribute action and doing peculiarly and specially to body

I will say and not even to body conjointly with the rational power; since body is a co-adjutor of that power, helping towards affording an abode for any form whatsoever in that body’s own self, seeing that it has become known to us that body along with the power will both become fit subjects for this form that has thus arisen; a subject however is to be stigmatized with nothing beyond simple passivity alone, whereas both these two are [aggressive] acts and deeds. Consequently this is an act peculiar to the power. And everything that, in its act which emanates from its own self, has had no need for another thing to help it, will not need in its own structure anything beyond its own self to help it, seeing that independence or isolation in the structure of self precedes independence or isolation in the putting forth of self-emanating action. Therefore this power is an essence standing of itself [independent of body]; and consequently the rational soul is an essence.


Among the proofs that guide (point) to the validity of this contention is what I am now going to say. No doubt a live body and live organs or instruments, if they accomplish their growing age and the age of standstill, begin to wither and diminish, to lose power and waste away, which in human beings is on passing 40 years.

Now, were the rational reasoning power a corporeal organic power, then there would be found not one single individual of mankind at these years of his age but what this power of his would have begun to diminish. But the case in most people is quite otherwise, nay indeed it is usual amongst the majority that as to intellectual power they improve in cleverness and increase in insight. Hence the structure of the rational power is not upheld by the body nor by the organ; and hence this power is an essence standing of itself, which is what we wished to show.


Among the proofs for the validity of this contention is the following also.

So much at least is clear, namely that not one of the bodily powers has the strength for performing infinite multifarious actions; and this is so because the strength of the one half of such a body will inevitably be found to be weaker than the strength of the whole; and the weaker is less powerful to perform and overcome than the stronger; and whatsoever, other than the infinite, gets less is itself finite; hence the strength of each one of the two halves is finite; hence too their sum is finite, since that the sum of two finites is itself finite, whereas it has been contended that it is infinite, which is a contradiction.

Hence the sound view is that the powers of bodies are not powerful enough to perform infinite manifold deeds. The rational power however is powerful enough to perform many infinite deeds, seeing that forms geometrical, arithmetical, and philosophical, which the rational power has to perform among other of its acts, are infinite. Therefore the rational power is not standing by and through the body, and hence therefore it stands of itself and is an essence of itself.

Further, so much at least is clear that the corruption of one of two conjoined essences does not entail and enjoin the corruption of the other: wherefore the death of the body does not render obligatory the death of the soul, which is what we wanted to show.

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