The human soul is either simple or composed; that is to say, either it is the whole and the same soul which thinks, feels, desires, calculates, perceives; or each faculty or manifestation of the soul.

Or the soul is made up of several faculties, separate and distinct from one another, which have each its own function, and nothing to do with the function of the others. The criterium of unity is merely by consciousness, in this latter case.

The soul may be composed in 2 ways:

a) In nature, as a body of skin, flesh and bone.

b) In degree, as a number of (...) which denote one unity, one ten, one hundred and so on. [...]

a) In the first case, the intellectual faculties, for instance, would be distinct from the animal propensities and thus there can be no combating of this theory as we combated that of the simple soul. This theory is against the unity of the soul.

b) In this case, there would be really a unity in the soul, but a kind of degree makes it of the nature of composed. Thus, in this theory, the intellectual faculties would be a superior aggregation of the particles or small things which form, for instance, the animal faculties. I do not know that this theory exists, but I have to consider it, inasmuch as it comes logically into my discussion.

Now whichever of these two hypotheses (theories) we accept, free‑will is inconsistent with both.

a) If the soul be simple, then its faculties being merely manifestations of the same thing have all the same nature.

If they have the same nature, then the intellectual faculties have the same nature as, for instance, the appetitive or the vegetative faculties.

From this results the strange conclusion that, if we own a man possible to make himself good or evil, we own him also able at will to make himself a genius or an idiot, intellectually a Kant or a grocer’s assistant. And this conclusion is manifestly false.

b) Let the human soul be composed; it may be composed in [different] ways. Firstly, the human faculties may be the same in composition, in fact, the same in nature but different from a material localization. (This is the theory of the Phrenologists, according to whom the faculties have the same composition i.e. the cerebral man — but different manifestations, according to their position in the head). Cf. Plato. Secondly, the human soul may be composed of faculties of entirely different nature and different material position, for instance, Plato’s theory.

In the first case, the will, being a manifestation of the human mind and all other faculties, e.g., the intellectus being susceptible of degrees, it is evident that the will itself is susceptible of degrees.

But could not the will be external to these, independent of them, powerful (or consciousness) over all? If so, then the power would extend (as in the case of the simple soul) to intellect and the same impossible conclusion should be obtained.

Thirdly, the human soul may be composed, as we may say, by degrees. Suppose the mind formed of any kind of monads or spiritual atoms; make out that a small grouping of these produces the lower faculties, and so on, progressively, the intellect being the highest aggregation. I do not think any one has ever held this theory, neither shall I call it mine; I have put it down here, merely because it comes naturally into the discussion.

Fourthly, the human soul may be composed both in nature and in degree; supposing, I mean to say, agglomerations of particles of different nature, rising in power, or, perchance, purifying itself to oneness and incomposition, as in the intellectual faculties.