Timaeus

And as He thus abode, His children gave heed to their Father’s command and obeyed it. They took the immortal principle of the mortal living creature, and imitating their own Maker, they borrowed from the Cosmos portions of fire and earth and water and air, as if meaning to pay them back, and the portions so taken they cemented together; but it was not with those indissoluble bonds wherewith they themselves were joined that they fastened together the portions but with numerous pegs, invisible for smallness; and thus they constructed out of them all each several body, and within bodies subject to inflow and outflow they bound the revolutions of the immortal Soul. The souls, then, being thus bound within a mighty river neither mastered it nor were mastered, but with violence they rolled along and were rolled along themselves, so that the whole of the living creature was moved, but in such a random way that its progress was disorderly and irrational, since it partook of all the six motions: for it progressed forwards and backwards, and again to right and to left, and upwards and downwards, wandering every way in all the six directions. For while the flood which foamed in and streamed out, as it supplied the food, was immense, still greater was the tumult produced within each creature as a result of the colliding bodies, when the body of a creature happened to meet and collide with alien fire from without, or with a solid lump of earth or liquid glidings of waters, or when it was overtaken by a tempest of winds driven by air, and when the motions due to all these causes rushing through the body impinged upon the Soul. And for these reasons all such motions were then termed Sensations, and are still so termed today. Moreover, since at that time they were causing, for the moment, constant and widespread motion, joining with the perpetually flowing stream in moving and violently shaking the revolutions of the Soul, they totally blocked the course of the Same by flowing contrary thereto, and hindered it thereby in its ruling and its going; while, on the other hand, they so shook up the course of the Other that in the three several intervals of the double and the triple, and in the mean terms and binding links of the 3/2, 4/3 and 9/8,—these being not wholly dissoluble save by Him who had bound them together,—they produced all manner of twistings, and caused in their circles fractures and disruptions of every possible kind, with the result that, as they barely held together one with another, they moved indeed but moved irrationally, being at one time reversed, at another oblique, and again upside down. Suppose, for example, that a man is in an upside down position, with his head resting on the earth and his feet touching something above, then, in this position of the man relative to that of the onlookers, his right will appear left to them, and his left right, and so will theirs to him.