This is rather a more delicate subject to handle than the last which we had occasion to treat of, viz: Heaven and Hell. For the reader’s sake, therefore, it must be treated at greater length; but before defining it, an exposition of the opinions of the most celebrated philosophers is necessary, which will be given in a few words, in order that the reader may be the better enabled to carry it along with him.

Their opinions are exceedingly varied. Some have pretended that the soul is a spirit or immaterial essence; others have maintained that it is a part of the Divinity; others assert that it is the concord of all parts of the body; and some uphold that it is the most subtle part of the blood, separated into the brain, and thence distributed through the nervous system. If this is established, the soul must take its origin from the heart which creates it; and the place where it exercises its noblest functions must be the brain, as that organ is the most purified from the grosser parts of the blood.

Such are a few of the different opinions which have been given to the world in regard to the soul. The better to develop them, we shall divide them into two classes. In the one will be found the statements of those philosophers who considered the soul as material; and in the other those of the opposite party, who maintained the doctrine of its immateriality.

Pythagoras and Plato have both maintained the doctrine that the soul was immaterial in its nature; that is, a being existing without aid from the body, and capable of action uncontrolled by any thing corporeal. They hold that all the individual spirits of animals were emanations from the universal Soul of the World, and that these off-givings were incorporeal, immortal, and of the same nature as the pervading Essence itself. They illustrated their doctrine well, by the analogy of a thousand little lights which are all of the same nature as the great flame at which they were kindled.

These philosophers believed that the universe was animated by an immaterial Essence, immortal and invisible, knowing everything, and acting always; and which is the cause of every movement, and the origin of all spirits, these being merely emanations from it. Then, as spirits are very subtle, they cannot unite (they observe) unless they can find a body subtle as the light, or as that expanded air which the vulgar take for heaven. They therefore assume a body less subtle, then another somewhat gross; and thus by degrees they come to be enabled to unite themselves to the bodies of animals, into which they descend as into dungeons or sepulchres. The death of the body, according to them, is the life of the soul, which was in a manner buried, and could only in a feeble way exercise its noblest functions. At the death of the body, the soul shakes off materiality, comes forth of its prison-house, and unites itself to the Soul of the World from which it emanated.

According to this opinion then, all the spirits of animals are of the same nature; and the diversity of their functions and faculties arises solely from the difference of the bodies into which they descend.

Aristotle supposes an universal intelligence, acting on particular intelligences, as light acts upon the eye; and that as light renders objects visible, so does this universal intelligence render the others intelligent.

This philosopher defines the soul as that whereby we live, feel, think, and move; but he is unsatisfactory as to the nature of that Being which is the source of its noblest functions. It is needless, therefore, to search in his writings for a solution of the difficulties which exist upon this subject.

Dicearchus, Asclepiades, and Galienus, have also, to a certain extent, believed that the soul was immaterial, but in a different way from that already alluded to. They suppose that the soul is nothing else than the harmony of all the parts of the body: that is, the result of an exact blending of its elements and disposition of its parts, its humours, and its essences. Thus, they say, as health is not a part of that which is healthy, although it is connected with it, so neither is the soul a part of the animal, although it be within it, but simply the harmony of all those parts which go to form the containing body.

On these opinions we must, remark, that their defenders believe in the immateriality of the soul on self-contradictory principles; for to maintain that, the soul is not a body, but merely something inseparably attached to a body, is to say that it is corporeal. We not only term that corporeal which is a body, but everything which has form and accident, and which cannot be separated from matter.

Such are the opinions of those philosophers who maintain that the soul is incorporeal or immaterial. We see that they are discordant and contradictory to each other, and consequently little to be heeded as points of faith. We now come to the opposite party, who have upheld the doctrine of its materiality.

Diogenes believed that the soul was composed of air, whence he deduces the necessity of respiration. He defines it as an air which passes through the mouth into the pulmonary vessels, whence it becomes warm, and whence it is distributed to every part of the system.

Leucippus and Democritus assert that it is fire, and that, like fire, it is composed of atoms which readily penetrate all parts of the body, and communicate motion to it.

Hippocrates said that it was composed of water and of fire. Empedocles thought that it was compounded of the four elements. Epicurus believed with Democritus that the soul is composed of fire, but he adds that there enter into its composition, air, a vapour, and an indescribable substance, which is the principle of thought. Out of these four different substances he makes to himself a very subtle spirit, pervading all the body, and which, he says, we ought to term the soul.

Descartes reasons also, but in a very wretched manner, that the soul is not material. I say in a very wretched manner, for never did philosopher reason so badly on this subject as did this great man. Here is his argument. He sets outs by saying that he must doubt in the existence of his own body, believing that there exists no such thing as a body at all, and then he reasons in this fashion: “There exists no body; I exist nevertheless: I am therefore not a body, and consequently I can only be a substance which thinks.” Although this fine reasoning destroys itself sufficiently, I will yet take the liberty of giving my opinion of it in two words.

1. The doubt which M. Descartes assumes is indefensible; for although one may sometimes think that he does not think that he has a body, it is true nevertheless that he has a body, since he thinks of it.

2. Whoever believes that there exists no body, ought to be well assured that he is not one himself; for no one can doubt in his own existence. If he is assured in this matter, his doubt is useless.

3. When he says that the soul is a substance which thinks, he tells us nothing new. Every person agrees in this; but the difficulty is to ascertain the nature of that substance which thinks, and in this respect M. Descartes is no wiser than his predecessors.

That we may not go crooked as he has done, and that we may form the soundest conception possible of the soul of all animals, without excepting man, who is of the same nature, and who only exercises different functions from the difference in his organization, it is important to attend to the following remarks.

It is certain that there exists in the universe a very subtle fluid, a substance extremely attenuated, whose source is the sun, and which pervades all other bodies, less or more, according to their nature and their consistence. Such is the soul of the world, which governs and vivifies it, and of which some portion is distributed to all the creatures in the universe.1

This soul is the purest fire. It burns not of itself, but by different movements, which it communicates to the particles of other bodies into which it enters, it burns and makest its warmth be felt. Our visible fire contains more of this matter than air; air, more than water; and earth, considerably less than any of them. Plants have more of it than minerals, and animals more than either. In fine, this fire pervading the body renders it capable of thought, and is that properly termed the soul, although it sometimes receives the appellation of animal spirits, which permeate the whole body. It is certain therefore that this soul being of the same nature as that of animals, is annihilated at the death of man, as it is at that of the other creatures. It follows that whatever poets and divines have told us of a future state, is only the chimerical offspring of their own brain, begotten and nourished by them for purposes which is by no means difficult to fathom.