We may now take the various specific types of Motion, such as locomotion, and once again enquire for each one whether it is not to be divided on the basis of direction, up, down, straight, circular- a question already raised; whether the organic motion should be distinguished from the inorganic- they are clearly not alike; whether, again, organic motions should be subdivided into walking, swimming and flight. Perhaps we should also distinguish, in each species, natural from unnatural motions: this distinction would however imply that motions have differences which are not external. It may indeed be the case that motions create these differences and cannot exist without them; but Nature may be supposed to be the ultimate source of motions and differences alike. Motions may also be classed as natural, artificial and purposive: "natural" embracing growth and decay; "artificial" architecture and shipbuilding; "purposive" enquiry, learning, government, and, in general, all speech and action. Again, with regard to growth, alteration and birth, the division may proceed from the natural and unnatural, or, speaking generally, from the characters of the moved objects.

Hence you inquire concerning the difference in the last things pertaining to them; but you leave uninvestigated such things as are first, and most hon...

And of things without life, plants, they say, are moved by transposition in order to growth, if we will concede to them that plants are without life. ...

Timaeus: Further, as concerns the motions, the best motion of a body is that caused by itself in itself; for this is most nearly akin to the motion...

For, after dividing "the animal" into mortal and immortal, then into terrestrial and aquatic; and the terrestrial again into those who fly and those w...

And then the name animal was reduced to definition, for the sake of perspicuity. But having discovered that it is distinguished from what is not an an...

At the end, likewise, of your inquiry, you introduce a distinction according to nature. For your question asks, “ How essences are known by energies,...

Of this I'll give thee here on earth an instance, which the eye can see. Regard the animals down here - a man, for instance, swimming! The water...

Such, then, is the method of the discovery [of truth]. For we must begin with the knowledge of the questions to be discussed. For often the form of...

Timaeus: and motion in non-uniformity; and the cause of the non-uniform nature lies in inequality. Now we have explained the origin of inequality ;...