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Generation of Animals

Generation of Animals

Book IV, 736b-737b

From: Aristotle: Generation of Animals (Greek). With an English translation by Arthur Leslie Peck, William Heinemann, London 1943, pp. 170-175.

Aristotle (384-322 BC) was a Greek philospher whose work proved enormously influential until the late Middle Ages. He wrote 'On the Generation of Animals' at around 350 AD.

semen is a residue of the nourishment that is under­going change.(a) It remains, then, that Reason alone enters in, as an additional factor, from outside, and that it alone is divine, because physical activity has nothing whatever to do with the activity of Reason.(b)  Now so far as we can see, the faculty of Soul: of every kind has to do with some physical substance which is different from the so-called "elements" and more divine than they are ; and as the varieties of Soul differ from one another in the scale of value, so do the various substances concerned with them differ in their nature. In all cases the semen contains within itself that which causes it to be fertile-—what , is known as " hot" substance," which is not fire nor any similar substance, but the pneuma which is enclosed within the semen or foam-like stuff,(d) and the natural substance which is in the pneuma; and this substance is analogous to the element which belongs to the stars.(e) That is why fire does not generate any animal,(f) and we find no animal taking shape either in fluid or solid substances while they are under the influence of fire ; whereas the heat of the sun (g) does effect generation, and so does the heat of animals,

ible, and divine (269 a 31 ff., 270 a 12 ff., 270 b 10 ff.-). Aristotle claims that it was vaguely recognized by the ancients, as is suggested by the name (aither) they gave to " the uppermost place " (270 b 16 ff.) : `απο του θ εν   ε ι  τον  `αίδιον  χρόνον θέμενοι  την  `επωνυμίαν  αυτω      (Cf... Hippocrates, π. ̀σάρκων 2 (viii. 584 Littré) δοκέι δέ μοι ο καλέομεν   θερμόν, αθάνατόν  τε ειναι     τουτο  ουνεξεχώρησεν  εις τηνανωτάτω περι φορην και αυτό μοι δοκέει αιθέρα τοις  παλαιοις ειρησθαι .) Its motion is circular; so is that of the stars, which are composed of it (289 a 15). It is not found in the sublunary regions, but pneuma is its " counterpart " (see Introd; §§ :70 ff., App. A §§ 7 ff., and B). (f) But see 761 b 15 ff., and note. (g) See App. A §§ 7 ff., B §§ 7-17.             


and not only the, heat of animals which operates through the semen, but also any other natural residue which there may be has within it a principle of life. Considerations of this sort show us that the heat which is in animals is not fire and does not get its origin or principle from fire. Consider now the physical part of the semen. [This it is which when it is emitted by the male, is accompanied by the portion of soul-principle and acts is its vehicle. Partly this soul-principle is separable from physical matter-this applies to those animals where some divine element is included, and what we call Reason is of this character—partly it is inseparable.) This physical part of the semen, being fluid and watery, dissolves and evaporates ; and on that account we should not always be trying to detect it leaving the female externally, or ,to find it is an ingredient of the fetation when that has set and taken shape, any more than we should expect to trace the fig-juice which sets and curdles milk. The fig-juice undergoes a change ; it does not remain is a part of the bulk which is set and curdled ; and the same applies to the semen.

We have now determined in what sense fetations and semen have Soul and in what sense they have not. They have Soul potentially, but not in actuality. As semen is a residue, and as it is endowed with the same movement as that in virtue of which the body grows through the distribution of the ultimate nourishment,(a) when the semen has entered the uterus it " sets " the residue produced by the female and imparts to it the same movement with which it is itself endowed. The female's contribution, of course, is a residue too, just, as the male's is, and


contains all the parts of the body potentially, though none in actuality ; and "all" includes those parts which distinguish the two sexes. Just as it sometimes happens that deformed (a) offspring are produced by deformed parents, and sometimes not so the offspring produced by a female are sometimes female, sometimes not, but male. The reason is that the female is as it were a deformed male ; and the menstrual discharge is semen, though in an impure condition; i.e., it lacks one constituent, and one only, the principle of Soul.(b) This explains why in the case of the wind-eggs produced by some animals, the egg which takes shape contains the parts of both sexes, (c) but it has not this principle, and therefore it does not become a living thing with Soul in it; this principle has to be supplied by the semen of the male, and it is when the female's residue secures this principle that a fetation is formed.(d)

(e) (When substances which are fluid but also corporeal are heated, an outer layer forms round, them, just as we find a solid layer forming round things that have been boiled, as they cool. All bodies depend on something glutinous to hold them together; and as their development proceeds and they become larger, this glutinous character is acquired by the substance known as sinew, which holds the parts of animals together (in some it is actual sinew which does this, in others its counterpart).(f) Skin, blood-vessels, membrane and all that class of substances are of the

(d) Or, " it becomes a fetation," i.e., a perfect fetation; see 737 a 10.

(e) The following paragraph, which consists partly of remarks taken from elsewhere, is irrelevant here.

(f) Sometimes, as here, " counterpart" could be represented by the modern term "analogue " ; cf.P.A. 653(b) 36.


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