Solivagus in Mundi wrote:
FJ, they certainly held that the fetus was a living organism prior to quickening, just not a truly human life. Indeed, if there is not the human soul then it isn't, in the proper sense, a human life. The form is what makes a thing to be this sort of thing. And the soul is the form. If it is human it has a human form, i.e. the rational soul
This has perplexed me - would the soul have changed from something else into a rational soul, then? I thought every creature had a soul.
No. The soul itself does not change. As far as contemporary Thomists saying things like that...I can see some River Forest being careless in their speech, but surely they know that such an idea would be anathema to Thomas!
Rather, the sensitive soul is suceeded by the rational soul. It is not subsumed or changed into it, but replaced by it.
Every living creature has a soul.
In question 118 of the prima pars we move to the production of the soul. St. Thomas affirms that the sensitive soul (the soul of animals) is not produced by an act of creation, but through the agent reproducing. The argument to the contrary, he states, rests on the premise that an animal soul is simple and self-subsisting. If this were true, then it would have to be made through creation. He denies the premise because, as he argued earlier, the animal soul does not subsist. The reason is that in brute animals, who have sensation but no intellect, there is no operation that is not involved with some organ. Since every operation then is of the composite
acting as a unity, there is no per-se operation of the animal soul. Since being follows upon operation, there is no warrant to claim that the animal soul is subsistent. It must then perish with the body.
Because of this it is not proper to speak of the animal soul being made, but rather the composite being made. It is the composite that exists, not the animal soul, except inasmuch as the existence of the composite is through the form. Hence, the soul is produced in the matter through corporeal agency, similar to non living things. The semen acts as a medium in the case of reproduction, it is an instrument of the generator. For St. Thomas the semen has a force that acts on the foetal matter given by the woman. The foetal matter has vegetative life and takes in nourishment. The force of the influence of the semen transmutes it until in some principal part the sensitive soul is present (the sensitive soul is not in the semen, but effect by the semen). Once this happens the semen is no longer exists as the semen gets dissolved. If we adapt his explanation to modern science, we may say that when the sperm joins the egg a change is effected such that in a principal part (say the nuclei of the egg) the form is already present. From thence, the substantial form in the body is able to work to the perfection of that body without any more need of influence from any sperm.
In the next article we find that we cannot say this about the human soul. Indeed, St. Thomas say that it is heretical to believe that the human soul is generated by the semen. The reason is that the human soul is intellectual. Now the intellect has an operation this does not involve the body, such as happens in understanding universals. Since this is the case, a material agent could never produce it. Further, this being the case, that it has a per se operation apart from the body, it is subsistent unlike the animal soul. Being simple and subsistent it needs be created by God. This holds true in every instance of human generation, not merely the creation of the
Several objections are raised. The most important is the second.
In man there is one and the same soul according to substance, intellective, sensitive and nutritive. But the sensitive soul is generated in man by the semen, just as in other animals, whence also the philosopher says in his book on the generation of animals that animal and man are not made at the same time, but first an animal is made have a sensitive soul. Therefore the intellective soul is also caused from the semen.
St. Thomas’ answer here is very informative. He rejects two positions pretty quickly. One is that the vital operations of the embryo are caused by the mother or the semen. But this cannot be because nourishment, growth, etc cannot be caused from an exterior principle. So at least the nutritive soul is present in the embryo from the get-go. He rejects also that there are three souls in man, where the intellectual soul stands as act to the sensitive soul, which stands as act to the nutritive soul. This is rejected because one must reject really the notion of substantial form to hold it.
The third position he argues at length against. This holds that the same soul evolves from nutritive, to sensitive and to intellectual. This position even affirms God doing this.
He rejects this for several reasons. One is that substantial form does not admit of more or less. By adding or subtracting we get a different species, just as by take a species of number, say 5, and adding unity, we no longer have the same species but a new one, viz. 6. The same identical form cannot belong to multiple species for an obvious reason that either the form would not be
the same, or the species would be identical. Second, an animal would come to be in a continuous motion. But in substantial change we do not have a lapse of time. Either this thing is a man or isn’t. He may be a man who is bleeding to death, but he is still fully a man while he is a man. Third, this would not be generation, which is always the bringing of a new thing into the matter and hence the end of an old thing, This against what we observe in nature. Lastly, we must either say that the intellectual soul is subsistent in which case it needs be distinct from the pre-existing form it evolved from or that like the pre-existing form it is not subsistent, but that is false.
The upshot for our inquiry here is that the soul must 1) be created and 2) cannot emerge or evolve.