(Our first encounter with the concept of the soul probably draws from popular tradition. Here the souls of the dead are just pale, lifeless shadows of their former selves, and can recognize Odysseus and behave like humans only after they had drank blood, as in the later vampire mythology).

"But when we had come down to the ship and to the sea, first of all we drew the ship down to the bright sea, and set the mast and sail in the black ship, and took the sheep and put them aboard, [5] and ourselves embarked, sorrowing, and shedding big tears. And for our aid in the wake of our dark-prowed ship a fair wind that filled the sail, a goodly comrade, was sent by fair-tressed Circe, dread goddess of human speech. So when we had made fast all the tackling throughout the ship, [10] we sat down, and the wind and the helms man made straight her course. All the day long her sail was stretched as she sped over the sea; and the sun set and all the ways grew dark.

"She came to deep-flowing Oceanus, that bounds the Earth, where is the land and city of the Cimmerians, [15] wrapped in mist and cloud. Never does the bright sun look down on them with his rays either when he mounts the starry heaven or when he turns again to earth from heaven, but baneful night is spread over wretched mortals. [20] Thither we came and beached our ship, and took out the sheep, and ourselves went beside the stream of Oceanus until we came to the place of which Circe had told us.

"Here Perimedes and Eurylochus held the victims, while I drew my sharp sword from beside my thigh, [25] and dug a pit of a cubit's length this way and that, and around it poured a libation to all the dead, first with milk and honey, thereafter with sweet wine, and in the third place with water, and I sprinkled thereon white barley meal. And I earnestly entreated the powerless heads of the dead, [30] vowing that when I came to Ithaca I would sacrifice in my halls a barren heifer, the best I had, and pile the altar with goodly gifts, and to Teiresias alone would sacrifice separately a ram, wholly black, the goodliest of my flocks. But when with vows and prayers [35] I had made supplication to the tribes of the dead, I took the sheep and cut their throats over the pit, and the dark blood ran forth. Then there gathered from out of Erebus the spirits of those that are dead, brides, and unwedded youths, and toil-worn old men, and tender maidens with hearts yet new to sorrow, [40] and many, too, that had been wounded with bronze-tipped spears, men slain in fight, wearing their blood-stained armour. These came thronging in crowds about the pit from every side, with a wondrous cry; and pale fear seized me. Then I called to my comrades and bade them flay and burn [45] the sheep that lay there slain with the pitiless bronze, and to make prayer to the gods, to mighty Hades and dread Persephone. And I myself drew my sharp sword from beside my thigh and sat there, and would not suffer the powerless heads of the dead [50] to draw near to the blood until I had enquired of Teiresias.

.............

[150] "So saying the spirit of the prince, Teiresias, went back into the house of Hades, when he had declared his prophecies; but I remained there steadfastly until my mother came up and drank the dark blood. At once then she knew me, and with wailing she spoke to me winged words:

[155] "‘My child, how didst thou come beneath the murky darkness, being still alive? Hard is it for those that live to behold these realms, for between are great rivers and dread streams; Oceanus first, which one may in no wise cross on foot, but only if one have a well-built ship. [160] Art thou but now come hither from Troy after long wanderings with thy ship and thy companions? and hast thou not yet reached Ithaca, nor seen thy wife in thy halls?’

"Just as," he said, "our soul, being air, holds us together, so do breath and air encompass the whole world." -- Aet. i. 3, 4 (R. P. 24).

He concludes that humans and other animals live and obtain a soul and mental faculties from this principle which is the air, saying the following:

‘...Humans and the other breathing animals live in the air, and this is their soul and mental faculties, as it will be clearly demonstrated in this study. And if this is removed, they die and their mental faculties abandon them.’

In another passage Diogenes clearly defines the soul as cold air:

The soul of all animals is this thing, air warmer than the external by which we are surrounded, but much colder than the one near the sun.

(One of the first attempts to explain cultures and social differences with biology. The soul here is the part of the person which includes behavioral traits and temperament.)

The other races in Europe differ from one another, both as to stature and shape, owing to the changes of the seasons, which are very great and frequent, and because the heat is strong, the winters severe, and there are frequent rains, and again protracted droughts, and winds, from which many and diversified changes are induced. These changes are likely to have an effect upon generation in the coagulation of the semen, as this process cannot be the same in summer as in winter, nor in rainy as in dry weather; wherefore, I think, that the figures of Europeans differ more than those of Asiatics; and they differ very much from one another as to stature in the same city; for vitiations of the semen occur in its coagulation more frequently during frequent changes of the seasons, than where they are alike and equable. And the same may be said of their dispositions, for the wild, and unsociable, and the passionate occur in such a constitution; for frequent excitement of the mind induces wildness, and extinguishes sociableness and mildness of disposition, and therefore I think the inhabitants of Europe more courageous than those of Asia; for a climate which is always the same induces indolence, but a changeable climate, laborious exertions both of body and mind; and from rest and indolence cowardice is engendered, and from laborious exertions and pains, courage. On this account the inhabitants of Europe are than the Asiatics, and also owing to their institutions, because they are not governed by kings like the latter, for where men are governed by kings there they must be very cowardly, as I have stated before; for their souls are enslaved, and they will not willingly, or readily undergo dangers in order to promote the power of another; but those that are free undertake dangers on their own account, and not for the sake of others; they court hazard and go out to meet it, for they themselves bear off the rewards of victory, and thus their institutions contribute not a little to their courage. Such is the general character of Europe and Asia.

(Plato here introduces the theory of re-incarnation, and for the first time the concept of a moral or an immoral soul. These views of Plato will have a huge impact upon Christian views on the soul)

"Clearly, Socrates, the soul is like the divine and the body like the mortal."

"Then see, Cebes, if this is not the conclusion from all that we have said, [80b] that the soul is most like the divine and immortal and intellectual and uniform and indissoluble and ever unchanging, and the body, on the contrary, most like the human and mortal and multiform and unintellectual and dissoluble and ever changing. Can we say anything, my dear Cebes, to show that this is not so?"

"No, we cannot."

"Well then, since this is the case, is it not natural for the body to meet with speedy dissolution and for the soul, on the contrary, to be entirely indissoluble, or nearly so?"

[80c] "Of course."

"Observe," he went on, "that when a man dies, the visible part of him, the body, which lies in the visible world and which we call the corpse, which is naturally subject to dissolution and decomposition, does not undergo these processes at once, but remains for a considerable time, and even for a very long time, if death takes place when the body is in good condition, and at a favorable time of the year. For when the body is shrunk and embalmed, as is done in Egypt, it remains almost entire for an incalculable time. And even if the body decay,

[80d] some parts of it, such as the bones and sinews and all that, are, so to speak, indestructible. Is not that true?"

"Yes."

"But the soul, the invisible, which departs into another place which is, like itself, noble and pure and invisible, to the realm of the god of the other world in truth, to the good and wise god, whither, if God will, my soul is soon to go,--is this soul, which has such qualities and such a nature, straightway scattered and destroyed when it departs from the body, as most men say?

[80e] Far from it, dear Cebes and Simmias, but the truth is much rather this--if it departs pure, dragging with it nothing of the body, because it never willingly associated with the body in life, but avoided it and gathered itself into itself alone, since this has always been its constant study--but this means nothing else than that it pursued philosophy rightly and [81a] really practiced being in a state of death: or is not this the practice of death?"

"By all means."

"Then if it is in such a condition, it goes away into that which is like itself, into the invisible, divine, immortal, and wise, and when it arrives there it is happy, freed from error and folly and fear and fierce loves and all the other human ills, and as the initiated say, lives in truth through all after time with the gods. Is this our belief, Cebes, or not?"

"Assuredly," said Cebes.

"But, I think, [81b] if when it departs from the body it is defiled and impure, because it was always with the body and cared for it and loved it and was fascinated by it and its desires and pleasures, so that it thought nothing was true except the corporeal, which one can touch and see and drink and eat and employ in the pleasures of love, and if it is accustomed to hate and fear and avoid that which is shadowy and invisible to the eyes but is intelligible and tangible to philosophy--do you think a soul in this condition [81c] will depart pure and uncontaminated?"

"By no means," said he.

"But it will be interpenetrated, I suppose, with the corporeal which intercourse and communion with the body have made a part of its nature because the body has been its constant companion and the object of its care?"

"Certainly."

"And, my friend, we must believe that the corporeal is burdensome and heavy and earthly and visible. And such a soul is weighed down by this and is dragged back into the visible world, through fear of the invisible and of the other world, and so, [81d] as they say, it flits about the monuments and the tombs, where shadowy shapes of souls have been seen, figures of those souls which were not set free in purity but retain something of the visible; and this is why they are seen."

"That is likely, Socrates."

"It is likely, Cebes. And it is likely that those are not the souls of the good, but those of the base, which are compelled to flit about such places as a punishment for their former evil mode of life. And they flit about [81e] until through the desire of the corporeal which clings to them they are again imprisoned in a body. And they are likely to be imprisoned in natures which correspond to the practices of their former life."

"What natures do you mean, Socrates?"

"I mean, for example, that those who have indulged in gluttony and violence and drunkenness, and have taken no pains to avoid them, are likely to pass into the bodies of asses and other beasts of that sort. [82a] Do you not think so?"

"Certainly that is very likely."

"And those who have chosen injustice and tyranny and robbery pass into the bodies of wolves and hawks and kites. Where else can we imagine that they go?"

"Beyond a doubt," said Cebes, "they pass into such creatures."

"Then," said he, "it is clear where all the others go, each in accordance with its own habits?"

"Yes," said Cebes, "of course."

"Then," said he, "the happiest of those, and those who go to the best place, are those who have practiced, [82b] by nature and habit, without philosophy or reason, the social and civil virtues which are called moderation and justice?"

"How are these happiest?"

"Don't you see? Is it not likely that they pass again into some such social and gentle species as that of bees or of wasps or ants, or into the human race again, and that worthy men spring from them?"

"Yes."

"And no one who has not been a philosopher and who is not wholly pure when he departs, is allowed to enter into the communion of the gods, [82c] but only the lover of knowledge. It is for this reason, dear Simmias and Cebes, that those who truly love wisdom refrain from all bodily desires and resist them firmly and do not give themselves up to them, not because they fear poverty or loss of property, as most men, in their love of money, do; nor is it because they fear the dishonor or disgrace of wickedness, like the lovers of honor and power, that they refrain from them."

(Aristotle addresses some methodological questions in the definition of the soul, and attempts to produce a methodical and logical construct).

Holding as we do that, while knowledge of any kind is a thing to be honoured and prized, one kind of it may, either by reason of its greater exactness or of a higher dignity and greater wonderfulness in its objects, be more honourable and precious than another, on both accounts we should naturally be led to place in the front rank the study of the soul. The knowledge of the soul admittedly contributes greatly to the advance of truth in general, and, above all, to our understanding of Nature, for the soul is in some sense the principle of animal life. Our aim is to grasp and understand, first its essential nature, and secondly its properties; of these some are taught to be affections proper to the soul itself, while others are considered to attach to the animal owing to the presence within it of soul.

To attain any assured knowledge about the soul is one of the most difficult things in the world. As the form of question which here presents itself, viz. the question 'What is it?', recurs in other fields, it might be supposed that there was some single method of inquiry applicable to all objects whose essential nature (as we are endeavouring to ascertain there is for derived properties the single method of demonstration); in that case what we should have to seek for would be this unique method. But if there is no such single and general method for solving the question of essence, our task becomes still more difficult; in the case of each different subject we shall have to determine the appropriate process of investigation. If to this there be a clear answer, e.g. that the process is demonstration or division, or some known method, difficulties and hesitations still beset us-with what facts shall we begin the inquiry? For the facts which form the starting-points in different subjects must be different, as e.g. in the case of numbers and surfaces.

First, no doubt, it is necessary to determine in which of the summa genera soul lies, what it is; is it 'a this-somewhat, 'a substance, or is it a quale or a quantum, or some other of the remaining kinds of predicates which we have distinguished? Further, does soul belong to the class of potential existents, or is it not rather an actuality? Our answer to this question is of the greatest importance.

We must consider also whether soul is divisible or is without parts, and whether it is everywhere homogeneous or not; and if not homogeneous, whether its various forms are different specifically or generically: up to the present time those who have discussed and investigated soul seem to have confined themselves to the human soul. We must be careful not to ignore the question whether soul can be defined in a single unambiguous formula, as is the case with animal, or whether we must not give a separate formula for each of it, as we do for horse, dog, man, god (in the latter case the 'universal' animal-and so too every other 'common predicate'-being treated either as nothing at all or as a later product). Further, if what exists is not a plurality of souls, but a plurality of parts of one soul, which ought we to investigate first, the whole soul or its parts? (It is also a difficult problem to decide which of these parts are in nature distinct from one another.) Again, which ought we to investigate first, these parts or their functions, mind or thinking, the faculty or the act of sensation, and so on? If the investigation of the functions precedes that of the parts, the further question suggests itself: ought we not before either to consider the correlative objects, e.g. of sense or thought? It seems not only useful for the discovery of the causes of the derived properties of substances to be acquainted with the essential nature of those substances (as in mathematics it is useful for the understanding of the property of the equality of the interior angles of a triangle to two right angles to know the essential nature of the straight and the curved or of the line and the plane) but also conversely, for the knowledge of the essential nature of a substance is largely promoted by an acquaintance with its properties: for, when we are able to give an account conformable to experience of all or most of the properties of a substance, we shall be in the most favourable position to say something worth saying about the essential nature of that subject; in all demonstration a definition of the essence is required as a starting-point, so that definitions which do not enable us to discover the derived properties, or which fail to facilitate even a conjecture about them, must obviously, one and all, be dialectical and futile.

A further problem presented by the affections of soul is this: are they all affections of the complex of body and soul, or is there any one among them peculiar to the soul by itself? To determine this is indispensable but difficult. If we consider the majority of them, there seems to be no case in which the soul can act or be acted upon without involving the body; e.g. anger, courage, appetite, and sensation generally. Thinking seems the most probable exception; but if this too proves to be a form of imagination or to be impossible without imagination, it too requires a body as a condition of its existence. If there is any way of acting or being acted upon proper to soul, soul will be capable of separate existence; if there is none, its separate existence is impossible. In the latter case, it will be like what is straight, which has many properties arising from the straightness in it, e.g. that of touching a bronze sphere at a point, though straightness divorced from the other constituents of the straight thing cannot touch it in this way; it cannot be so divorced at all, since it is always found in a body. It therefore seems that all the affections of soul involve a body-passion, gentleness, fear, pity, courage, joy, loving, and hating; in all these there is a concurrent affection of the body. In support of this we may point to the fact that, while sometimes on the occasion of violent and striking occurrences there is no excitement or fear felt, on others faint and feeble stimulations produce these emotions, viz. when the body is already in a state of tension resembling its condition when we are angry. Here is a still clearer case: in the absence of any external cause of terror we find ourselves experiencing the feelings of a man in terror. From all this it is obvious that the affections of soul are enmattered formulable essences.

Consequently their definitions ought to correspond, e.g. anger should be defined as a certain mode of movement of such and such a body (or part or faculty of a body) by this or that cause and for this or that end. That is precisely why the study of the soul must fall within the science of Nature, at least so far as in its affections it manifests this double character. Hence a physicist would define an affection of soul differently from a dialectician; the latter would define e.g. anger as the appetite for returning pain for pain, or something like that, while the former would define it as a boiling of the blood or warm substance surround the heart. The latter assigns the material conditions, the former the form or formulable essence; for what he states is the formulable essence of the fact, though for its actual existence there must be embodiment of it in a material such as is described by the other. Thus the essence of a house is assigned in such a formula as 'a shelter against destruction by wind, rain, and heat'; the physicist would describe it as 'stones, bricks, and timbers'; but there is a third possible description which would say that it was that form in that material with that purpose or end. Which, then, among these is entitled to be regarded as the genuine physicist? The one who confines himself to the material, or the one who restricts himself to the formulable essence alone? Is it not rather the one who combines both in a single formula? If this is so, how are we to characterize the other two? Must we not say that there is no type of thinker who concerns himself with those qualities or attributes of the material which are in fact inseparable from the material, and without attempting even in thought to separate them? The physicist is he who concerns himself with all the properties active and passive of bodies or materials thus or thus defined; attributes not considered as being of this character he leaves to others, in certain cases it may be to a specialist, e.g. a carpenter or a physician, in others (a) where they are inseparable in fact, but are separable from any particular kind of body by an effort of abstraction, to the mathematician, (b) where they are separate both in fact and in thought from body altogether, to the First Philosopher or metaphysician. But we must return from this digression, and repeat that the affections of soul are inseparable from the material substratum of animal life, to which we have seen that such affections, e.g. passion and fear, attach, and have not the same mode of being as a line or a plane.

What is called a living being? ... If one calls ‘living being’ something that eats and grows, we should ask again whether he thinks that plants are ‘living beings’ ... for Plato calls ‘living beings’ the plants too, which share only the third part of the soul, the one which is the seat of the desires, while Aristotle thinks that the plants share the vegetative and nutrient soul, but he does not go as far as calling them ‘living beings’, for he only calls a ‘living being’ the one which shares the other, the sensate soul ... Thus, according to Plato, the plant has a soul and is a living being, but according to Aristotle, it is not a living being yet, because it does not have sensation, but it has a soul... But according to the Stoics the plant is neither animated, nor a living being, because a living being is something with a soul.

(The author explores the issues of the soul and human identity in relation to the foetus. His account is a compilation of a number of previous theories on the soul. He examines the functions of the soul in the body, and although he adopts the Aristotelian/Herophilean model of the soul as a set of faculties, he also accepts the Platonic view of a leading immortal entity part of the celestial world, and the soul that animates the universe).

A living being is an essence with soul and sense, as far as the general characteristics of all its categories are concerned.

Chapter 3. It would be possible to prove wrong those who said that what is carried in the womb is not a living being if we were to examine what has been said. [166] I will now explain how many and what kind of things a living being does. As a living being consists of a soul and a nature, it needs food and air, because the soul is fed with air, while the nature is fed with liquid and solid food. Now, we will find that what is carried in the womb is making use of all the resources, the ones needed for the motion of the soul, and those needed for the development of the nature. Hippocrates thinks that it swallows, and says that it breathes through the mouth and the nose. Some of the Asclepiads think that it also sucks milk from the suckers in womb and digests, since it is necessary to digest what has been consumed, even though it receives the nutriment already highly processed by the mother. But it would not be possible to assimilate the received nutriment unless the nature suitable to receive it is already present. It would be necessary for the one who feeds the nature of the child to resemble the one who is fed. Then it would be ready to give and take the works of nature, and prepared to make distinctions and single out what is alien. Thus the biles, [167] and all the humours are made, once the food is separated.  Moreover, one should not think that the only nutrient material for the embryo is the one that comes through the umbilical cord to the liver, because it is also fed through these avenues, and especially the most perfected ones, and when the nutrient goes down that route, it enjoys food. Do not think that because Hippocrates said ‘the first nutrient is supplied through the umbilical cord’ he was not aware that it is also fed through the mouth, for he mentioned that route too, as it has been explained above. The fact that once it is born it is instinctively drawn to the breast provides additional proof that it is fed through the mouth while still in the womb, otherwise it would not rush so quickly in this direction if it had not already been accustomed to it. And it has the ability to break the ingested nutriment into vapour and spirit, and easily adds it to each one of its own particles. It can also turn the nutriment from the seed into humours and the one from the humours into flesh, veins, nerves, arteries, bones, guts and limbs. It becomes much from little, and big from small, while its capacity to grow allows it to expand and become complete until it has reached the limits of its in-built potential.
[168] Chapter 4: We have sufficiently illustrated in our speech the works of nature in the womb. In the following lines I will try to demonstrate that it also possesses soul and intellect. Since the sensory organs are constructed in such a manner that the powers of the soul can be transported through them, the sight through the eyes, the hearing through the ears, the taste and smell through the tongue and the nose, and the touch through the hands and body contact, it is obvious that no part of the body has been left idle. However, the embryo in the womb is predetermined to have the aforementioned places, and it already has from the beginning the essence of the soul and the brain, which is its place of residence, implanted in the recess of the head. It is clear that, along with the ejaculation of the seed into the uterus, the creator of the world sowed the soul too, in order to provide, along with the body, its governing power. We know that those who create instruments construct them in such a way as to be able to fulfil certain functions. [169] The ship-builder constructs the keel underneath the ship so as to be able to cut through the waves and serve as a wall and safe barrier against underwater rocks. The flute-maker shapes the copper into long tubes suitable for receiving the wind blown into them. The musician stretches the strings so that they can produce a harmonious tune. The person who prepares healing medicines does so for the purpose of curing disease. The general gives tactical orders to those in battle-formation so that they can sustain an attack by the enemy.  As those who perform any of those functions do so in preparation for a certain task, in the same manner nature creates each organ inside us for the purpose of performing a certain task. So, the nature of the nerves, which is the residence of the soul as it grows together with the spirit, indicates that the soul is created simultaneously with the body. And if the eye cannot see yet, and the tongue cannot taste, and the ear cannot hear, and the touch cannot actually feel the hot, or cold, or moist, or dry, still this potential exists latent, and soon after the baby is born [170] it can do all these. But, I would dare say that inactivity is action, because keeping the eyes shut, and the nose contracted, and the ears inactive, while still in the uterus, is the work of a commanding soul. On the other hand, one could not argue that the tongue of the foetus does not experience taste, or that it does not sense the quality of substances, and this can be proven through the investigation of accidents. We know that often children died in the womb because of the bad quality of orally consumed substances, as they turned away and rejected the food. Nature conveyed this information through the capacity of the tongue to taste, in the interests of the self-preservation of the foetus. Breathing is also the work of the soul in embryos, since they breath through the mouth, as we have already mentioned. This also indicates that the soul and the seed are both present in the creation of the nature, because most doctors have defined breathing as an activity of the soul, not one of the body. It would be childish to argue that breathing is not an activity of the soul on the grounds that those who are asleep are still breathing [171] spontaneously, even though breathing can be intentional too. While the living being is awake, the soul is in charge of all actions, it sees, hears and functions through the rest of the sensory organs, it moves, and becomes aware of things through the sense, and is in charge of everything. By spreading itself in all directions and diffusing itself through the organs if performs all necessary functions. In the same manner, at night-time, it contracts and brings itself together, and it is not disturbed by what can be seen, or alerted by what can be heard, or distracted by what can be felt through smell, or altered by what is encountered through touch, or getting tired by running or walking or other physical exercise, or getting involved into such things, and so it can perform the function of breathing. Alternatively, we may suppose that nature willingly does what it should do, and not because someone else is doing it on its behalf, while the soul, since it participates in a more divine share, does not follow the same course of action. The nature is mortal and earthly and outside the boundaries of the intellect, and it does not possess the ability to reason. It knows only the mortal world, and is corruptible. However, the soul [172] is a segment of the universal soul, and possesses the knowledge of the celestial chorus, and on its way towards its own kind it surpasses the earth, it turns away from the fallacy of the water, it rises into the air, becomes superior to fire, and encounters the celestial divinity. It often sees the place above the sky, mixes with the supreme master, becomes a traveller of those places above, encounters its own kind, and is aware of its origins, even though it may be living in a body. The universal father knows everything through the eyes of the soul. So, no one should argue that breathing while the body is idle in sleep takes place without the knowledge of the soul. The soul is more capable and stronger than the body in everything. The body has the same capacity whether one is asleep or not. It digests, distributes, separates, adds and develops in both instances. However, only the soul of those who are awake does what is appropriate for the body, while the soul of those who are asleep cannot.