The discussion of these difficulties, however, is a task appropriate to a different investigation:’ let us return to the ‘elements’ of which bodies are composed. The theories that ‘there is something common to all the “elements”’, and that they are reciprocally transformed’, are so related that those who accept either are bound to accept the other as well. Those, on the other hand, who do not make their coming-to-be reciprocal-who refuse to suppose that any one of the ‘elements’ comes-to-be out of any other taken singly, except in the sense in which bricks come-to-be out of a wall-are faced with a paradox. How, on their theory, are flesh and bones or any of the other compounds to result from the ‘elements’ taken together?

Indeed, the point we have raised constitutes a problem even for those who generate the ‘elements’ out of one another. In what manner does anything other than, and beside, the ‘elements’ come-to-be out of them? Let me illustrate my meaning. Water can come-to-be out of Fire and Fire out of Water; for their substralum is something common to them both. But flesh too, presumably, and marrow come-to-be out of them. How, then, do such things come to-be? For (a) how is the manner of their coming-to-be to be conceived by those who maintain a theory like that of Empedocles? They must conceive it as composition-just as a wall comes-to-be out of bricks and stones: and the ‘Mixture’, of which they speak, will be composed of the ‘elements’, these being preserved in it unaltered but with their small particles juxtaposed each to each. That will be the manner, presumably, in which flesh and every other compound results from the ‘elements’. Consequently, it follows that Fire and Water do not come-to-be ‘out of any and every part of flesh’. For instance, although a sphere might come-to-be out of this part of a lump of wax and a pyramid out of some other part, it was nevertheless possible for either figure to have come-to-be out of either part indifferently: that is the manner of coming-to-be when ‘both Fire and Water come-to-be out of any and every part of flesh’. Those, however, who maintain the theory in question, are not at liberty to conceive that ‘both come-to-be out of flesh’ in that manner, but only as a stone and a brick ‘both come-to-be out of a wall’-viz. each out of a different place or part. Similarly (b) even for those who postulate a single matter of their ‘elements’ there is a certain difficulty in explaining how anything is to result from two of them taken together-e.g. from ‘cold’ and hot’, or from Fire and Ear............