Chapter 8
Some proofs, given by the ancients, for the simplicity of
the soul coincide with our own
453. Let us compare these proofs of the simplicity of the sensitive soul with those given by the ancients. The older proofs will perhaps be clearer if expressed in our terminology. Certainly, I make no claim to originality in what I have said. I have only said it anew to render it more easily understandable to contemporaries.
I. One proof of the simplicity of the soul was deduced by the ancients from the soul's presence, whole and entire, in every part of the body, as we have seen. A 6th century author writes:
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Do you admit that the entire soul is diffused through all the individual members, or that a greater part of it is present in a larger member and a lesser part in a smaller member? - I think rather that it is entire in each member of the body. Although it is circumscribed in some way, I do not believe that it is in any way composed of parts because it remains whole despite any truncation of the bodily members.(199) |
This proof is extremely convincing, granted proof of the soul's true presence in every part of the body per contactum virtutis. Doubts were raised on this point, however, which diminished persuasion of the proof, although a careful examination of the way in which the soul feels restores the balance and redoubles the force of the proof. Examination shows that continuous extension can exist only in a non-extended ens. It certainly follows from this that the soul is in every part of its body. Indeed, its whole sensible body, as felt, is in the soul as in a simple principle through the relationship we called sensility.(200) We ought also to note that all the extrasubjective phenomena of life are manifested, as I said, in a body felt subjectively.
It is clear, therefore, that the soul gives the living body its wonderful unity:
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Wonder at our Maker, and at the way in which he united the effective force of your soul to the body. The soul moves into the body, as it were, and invades even its external particles. Infusing its power there, it draws the most distant members together in a single, harmonious, social concord.(201) |
454. II. Aristotle argues for the simplicity of the soul from the fact that it knows all bodies indifferently.(202) He says that the soul, if it were some determined body, would not know other bodies. St. Thomas develops the argument in this way:
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Anything capable of knowing several things cannot have anything of them in its own nature. If it did, this would prevent it from knowing other things. So, for example, the tongue of a person suffering from some bitter, choleric disturbance cannot perceive anything sweet. Everything seems bitter to him. Similarly, if the intellectual principle had in itself the nature of a body, it would be incapable of knowing all bodies which, as we must see, all have a determined nature. It is impossible, therefore, for the intellectual principle to be a body. Likewise, it is also impossible for it to understand by means of a bodily organ. If this were the case, the determined nature of that bodily organ would prevent the knowledge of all bodies.(203) |
The Scholastics had a great deal to say about this argument, although others have often found it inefficacious. My own opinion is that it is highly effective provided the foundation is clearly explained. The argument should first be directed to proving the simplicity of the sensitive principle, not the intellective which comes later as a consequence. The sentient principle is first to perceive real bodies; the intellective principle only apprehends and affirms them as felt. If the sensible perception of bodies could be explained by supposing the sentient, perceiving principle to be corporeal, the later intellective operation would cause no trouble; it would receive matter just as it was given to it. But proof that the sentient principle cannot be corporeal lies in this argument: if it were a determined body, it would never feel its own or other bodies' extension because it would not be entirely the same in every part, and consequently would not be any of the phenomena manifested in extension. In other words, it would not be able to feel at all. This is in fact the first proof that I gave of the simplicity of the sentient principle.(204) It is irrepugnable.
Notes
(199) John Maxentius, Dial. 2, Contr. Nest. (AD 505).
(200) AMS, 230-234.
(201) St. Basil, Homil. in illud 'Attende tibi'.
(202) De Anima, bk. 3, c. 5.
(203) S.T., I, q. 75, art. 2.
(204) AMS, 94-103.