An intellectual substance is an angel. Grab yourself a quiet seat, dear reader; we have a long chapter ahead of us this week.
1 An intellectual substance has still another kind of knowledge of God. Indeed, it has been stated in Book Two [96ff] that a separate substance, in knowing its own essence, knows both what is above and what is below itself, in a manner proper to its substance. This is especially necessary if what is above it is its cause, since the likeness of the cause must be found in the effects. And so, since God is the cause of all created intellectual substances, as is evident from the foregoing, then separate intellectual substances, in knowing their own essence, must know God Himself by way of a vision of some kind.
For a thing whose likeness exists in the intellect is known through the intellect by way of vision, just as the likeness of a thing which is seen corporeally is present in the sense of the viewer. So, whatever intellect understands a separate substance, by knowing what it is, sees God in a higher way than He is known by any of the previously treated types of knowledge.
Notes Regular readers will understand this kind of vision is a certain kind of induction; hence induction can be the highest form of knowledge.
Notes Recall a phantasm is a conglomeration of sense impressions, the stuff offered by your biology to your intellect.
2 Hence, since some men have claimed that man’s ultimate end is in this life, because they know separate substances, we must consider whether man can know separate substances in this life.
Now, on this point there is some dispute. For, our intellect in our present state understands nothing without a phantasm, and the phantasm is related to the possible intellect, whereby we understand, as colors are related to vision, as is evident from what we have treated in Book Two.
Therefore, if any of us could achieve the understanding of separate substances through the intellectual knowledge which is from phantasms, then it would be possible for a person in this life to understand separate substances themselves. Consequently, by seeing these separate substances one will participate in that mode of knowledge whereby the separate substance, while understanding itself, understands God. But, if one cannot in any way attain to the understanding of separate substances through the knowledge which depends on phantasms, then it will not be possible for man in the present state of life to achieve the aforesaid mode of divine knowledge.
Notes Recall quiddity is whatness or essence. Might help to think of quddities of quddities as higher abstractions.
3 Now, various people have claimed in different ways that we could reach an understanding of separate substances from the knowledge which is accomplished through phantasms.
For instance, Avempace claimed that, through the study of the speculative sciences, we can, on the basis of things understood through phantasms, reach an understanding of separate substances. For we can by the action of the intellect abstract the quiddity of anything that has a quiddity, and which is not identical with its quiddity.
Indeed, the intellect is naturally equipped to know any quiddity, in so far as it is quiddity, since the proper object of the intellect is what a thing is. But, if what is primarily understood by the possible intellect is something having a quiddity, we can abstract through the possible intellect the quiddity of that which is primarily understood. Moreover, if that quiddity also has a quiddity, it will in turn be possible to abstract the quiddity of this quiddity.
And since an infinite process is impossible, it must stop somewhere. Therefore, our intellect is able to reach, by way of resolution, the knowledge of a quiddity which has no further quiddity. Now, this is the sort of quiddity proper to a separate substance. So, our intellect can, through the knowledge of those sensible things that is received from phantasms, reach an understanding of separate substances.
4 He proceeds, moreover, to show the same thing in another, similar way. For he maintains that the understanding of one thing, say a horse, is plurally present in me and in you, simply by means of a multiplication of spiritual species which are diversified in me and in you. So, then, it is necessary that an object of understanding, which is not based on any species of this kind, be identical in me and in you.
But the quiddity of an object of understanding, which quiddity our intellect is naturally capable of abstracting, has no spiritual but individual species, as we have proved, because the quiddity of a thing that is understood is not the quiddity of an individual, either spiritual or corporeal, for a thing that is understood, as such, is universal. So, our intellect is by nature capable of understanding a quiddity for which the understanding is one among all men. Now, such is the quiddity of a separate substance. Hence, our understanding is naturally equipped to know separate substance.
5 However, if a careful consideration be made, these ways of arguing will be discovered to be frivolous. Since a thing that is understood, as such, is universal, the quiddity of the thing understood must be the quiddity of something universal; namely, of a genus or a species. Now, the quiddity of a genus or species pertaining to these sensible things, whose intellectual knowledge we get through phantasms, includes matter and form within itself. So, it is entirely unlike the quiddity of a separate substance, which latter is simple and immaterial. Therefore, it is not possible for the quiddity of a separate substance to be understood, simply because the quiddity of a sensible thing is understood through phantasms.
6 Besides, the form which in actual being cannot be separated from a subject is not of the same rational character as the form which is separated in its being from such a subject, even though both of them can be taken, in an act of consideration, without such a subject. Thus, there is not the same essential character for magnitude and for a separate substance, unless we claim that magnitudes are separate things midway between specific forms and sensible things, as some of the Platonists maintained.
Of course, the quiddity of a genus or species of sensible things cannot be separate in actual being from a given material individual, unless, perhaps, we maintain with the Platonists separate forms of things, but this has been disproved by Aristotle. Therefore, the quiddity of the aforementioned separate substances, which in no way exist in matter, is utterly different. Therefore, separate substances cannot be understood simply by virtue of the fact that these quiddities are understood.
7 Again, if it is granted that the quiddity of a separate substance is of the same rational character as the quiddity of a genus or species of these sensible things, that does not warrant saying that it is of the same rational character specifically, unless we say that the species of sensible things are themselves separate substances, as the Platonists claimed. The conclusion stands, then, that they will not be of the same rational character, except according to the rational character of quiddity as quiddity.
Now, this is a meaning of rational character which is common to genus and to substance. Therefore, nothing except their remote genus could be understood concerning separate substances through these sensible quiddities. Now, the fact that the genus is known does not mean that the species is known, except in potency. So, separate substances could not be understood through an understanding of the quiddities of these sensible things.
8 Moreover, there is a greater difference between separate substances and sensible things than between one sensible thing and another. But to understand the quiddity of one sensible thing is not enough to enable one to understand the quiddity of another sensible thing. For instance, a man who is born blind is not at all enabled to achieve understanding of the quiddity of color simply because he understands the quiddity of sound. Much less, then, is one enabled to understand the quiddity of a separate substance by the fact that he understands the quiddity of a sensible substance.
9 Furthermore, even if we claim that separate substances move the spheres, and that from their motions the forms of these sensible things are produced, this way of knowing separate substance, from sensible things, does not suffice for a knowing of their quiddity.
For a cause is known through an effect, either by reason of a likeness which exists between the effect and the cause or in so far as the effect shows the power of the cause.
Now, it would not be possible to know from the effect, by reason of likeness, what the cause is unless the agent is of one species with the effect. But that is not the way separate substances are related to sensible things. On the other hand, on the basis of power, this cannot be done except when the effect is equal to the power of the cause. For, in that case, the whole power of the cause is known through the effect, and the power of a thing demonstrates its substance. But this cannot be asserted in the present case, for the powers of separate substances exceed all the sensible effects which we may grasp intellectually, as a universal power surpasses a particular effect. Therefore, it is not possible for us to be enabled, through an understanding of sensible things, to come to an understanding of separate substance.
10 Again, all intelligible objects whose knowledge we reach through investigation and study belong to some one of the speculative sciences. So, if we attain the understanding of separate substances as a result of our understanding of the natures and quiddities of these sensible things, then it must be that the understanding of separate substances depends on one of the speculative sciences. Yet we do not observe this; there is no speculative science which teaches what any of the separate substances is, but only that they are. So, it is not possible for us to reach an understanding of separate substances simply because we understand sensible natures.
11 On the other hand, if it be suggested that such a speculative science is possible, even though it has not yet been discovered, this is no argument, because it is not possible to arrive at an understanding of the aforesaid substances through any principles known to us. Indeed, all the proper principles of any science depend on first indemonstrable principles, which are self-evident, and we get our knowledge of these from the senses, as is shown at the end of the Posterior Analytics. However sensible things are not adequate guides to the knowledge of immaterial things, as we have proved by the arguments above. Therefore, it is not possible for there to be any science whereby one might achieve understanding of separate substances.