The Soul

 

                                                     

                

 

THE SOUL

 

          The distinction between actuality and potentiality, the principle that effects are contained in their causes either “formally” or “eminently,” and that final causality pervades the natural order, in fact have the most dramatic consequences for the debate between religion and atheism.

          We want now to examine how some of these principles were applied by Aquinas and the Scholastic tradition in general to a defense of the immortality of the soul and the natural law conception of morality.

 

The Soul

For Aristotle a soul is just the form or essence of a living thing. One should not think of some ghostly object of the sort that floats away from a body after death. The soul is just a kind of form.

The soul of a plant is what Aristotelians call a “nutritive soul”; and that is just a form or essence that gives a thing that has it the powers of taking in nutrients, growing, and reproducing itself.

 

The soul of a non-human animal is called a “sensory soul” and it is just a form or essence that gives  a thing that has it both the powers of a nutritive soul, and also an animal’s distinctive powers of being able to sense the world around it and to move itself.

When we come to human beings we have what is called a “rational soul” which includes both the powers of the nutritive and sensory souls and also the distinctively human powers of intellect and will. So there is a natural hierarchical relationship between the souls.

 

A thing having certain form goes hand in hand with its having a certain final cause or natural end. A human being has all the ends of the sensory and nutritive soul, but on top of them he has the ends or final causes entailed by being rational and having free will. Rationality has its natural end or final cause in the attainment of truth. Free will has as its natural end or final cause the choice of those actions that best accord with the truth about the human nature being’s own nature or essence.

Morality, according to Aristotle and Aquinas, is the habitual choice of actions that further the hierarchically ordered natural ends entailed by human nature. We have seen that the deepest truth about the world is that it is caused and sustained by God. The highest fulfillment then of the power of the intellect then is to know God. The highest fulfillment of free choice is to live in a way that facilitates the knowing of God.

 

The power of the intellect cannot possibly require a material or bodily organ for its operation. Central to the intellect’s operation is its grasp of forms, essences, or universals, and other abstractions like propositions. The immaterial nature of these things entails that the intellect which grasps them must itself be immaterial as well. How so?

We apprehend the ‘universals’. The form of “dogness” that exists in our minds when we think about dogs is the same form that exists in actual dogs. This is grasping what they are. What they are is determined by their essence or form. If the intellect is a material thing—some part of the brain, then for the form to exist in the intellect is for the form to exist in a certain material thing; for example, for the form of “dogness” to exist in a certain parcel of matter is just for that parcel of matter to be a dog. In that case, if your intellect was just the same thing as some part of your brain, it follows that that part of your brain would become a dog whenever you thought about dogs. “But that’s absurd!” Assuming that the intellect is material leads to such absurdity; hence the intellect is not material.

The thought we are having must be as determinate as triangularity itself, otherwise it just wouldn’t be a thought about triangularity per se, but only a thought about some approximation of triangularity. Material triangularity is only ever an approximation. It follows that the thought about triangularity is not material. Suppose a thought about triangularity consist of some physical representation in the brain somewhere (in the form of a neuronal firing pattern or some such thing). Like any other physical representation of a triangle, this one too would be just one particular material thing among others, not universal at all. Again the idea that thought is a purely a material operation of the brain makes no sense.

Aquinas’s claim isn’t a “soul of the gaps” analogue to “God of the gaps” arguments. He is not speculating that there might be some ghostly objet floating around in there. He is saying that given the facts about universals, and our thoughts about them, it is conceptually impossible (not merely improbable) for the intellect to be material. One thing neuroscience won’t “discover” is that thought is a material operation of the brain, any more than it will “discover” that 2+2=5.

The soul of a man is not a complete substance; only the soul and body (i.e. the form and matter) together constitute a thing or substance, that is, a man. It is the man himself who thinks, just as it is the man himself and not the soul who grows taller, digests his food, and walks around. For this reason human thoughts correlate with certain brain events even if it is not identical to any of them. The operation of the intellect and will constitute the formal-cum-final cause of the action, of which the firing of the neurons, flexing of the muscles, are the material cause.

The intellect itself operates without bodily organ, it does depend indirectly on the senses for the raw material from which it abstracts universals or essences (triangularity from particular triangles). The soul as it does in thought can function apart from the matter it informs, then it can also exist apart from the matter it informs, as a kind of incomplete substance. Potentiality can never exist without actuality; but actuality can and does exist without potentiality, namely in God who is pure actuality.

Similarly matter can never exist without form; but form can exist without matter, and does in this case, at least after death, when the matter of the body is not longer inform by the soul, its form.  The soul as it does, partially operating and thus existing as it does apart from the body even when informing it, does not thereby die. For a thing to perish is just for it to lose its form. But the soul doesn’t lose its form, because it is a form.