Aristotle · a new plain-English translation from the original language
1| Why do we walk with difficulty up sloping ground? Is it because every act of walking is completed out of a lifting and a placing of the foot? Now the lifting is contrary to nature, the placing is in accordance with nature, and the setting-forward is a mean between the two; but in walking up a slope there is much that is contrary to nature. Why do those who fall from horses suffer less harm? Is it because, out of fear, they guard themselves more? Book 6. Problems Arising from How Things Are Positioned and Shaped Why does sitting make some people fatter, and others thinner? Is it 〈because〉 their states differ? For some are hot, others cold. Now the hot grow fat, since the body masters the food because of its heat; but those who are chilled, because they need heat brought in from outside, and the body is most affected by this through movements, cannot digest food while at rest. Or is it because some are full of residue and need motion to use it up, while others are not? Why must one produce a stretching of the parts, as the person who exercises does? Is it because the pores must be cleared out by the body's own breath?
2| Why is it better to lie curled up, and many people, including doctors, recommend this? Is it because the stomach, being warmed, digests faster? And curling up warms it more. Further, one must give the winds a place against which to press; for in this way the flatulence will cause the least trouble. This is also why boils and other abscesses are healthy, because they have cavities into which they receive the winds. Now when the body is stretched out, no cavity forms (for the internal organs occupy the whole space), but when it is bent, one forms. Why does dizziness occur more in those standing up than in those sitting down? Is it because, when at rest, the fluid inclines all together toward one part? But fluid that is in motion is uniformly distributed. So people grow dizzy on standing up after being at rest, when they are in this condition; but they sit down after having been in motion, when the fluid is evenly distributed and dispersed. Why does sleep come over people more readily when they lie on their right side? Is it because people are disposed oppositely when awake and when asleep? Since, then, people lie on their left side when awake, the opposite will hold from another starting point, the contrary one. Or is it because sleep is a lack of motion? So the parts that produce motion must be at rest, and the right side is the motive one. So when people lie in this position, some waking principle is, as it were, bound down.