Archimedes
Archimedes

I thought fit to… explain in detail in the same book the peculiarity of a certain method, by which it will be possible… to investigate some of the problems in mathematics by means of mechanics. This procedure is… no less useful even for the proof of the theorems themselves; for certain things first became clear to me by a mechanical method, although they had to be demonstrated by geometry

afterwards… But it is of course easier, when we have previously acquired, by the method, some knowledge of the questions, to supply the proof than it is to find it without any previous knowledge.

Aristóteles
Aristóteles

[L]et us consider, with respect to causes, what they are, and how many there are in number… this also must be done by us in discoursing concerning generation and corruption, and all physical mutation… knowing the principles of these…
Cause… is after one manner said to be that, from which, being inherent, something is produced… But after another manner cause is form and paradigm (and

this is the definition of the essence of a thing) and the genera of this. …But it happens… that there are also many causes of the same thing, and this is not from accident. …seed, a physician, he who consults, and, in short, he who makes, are all of them causes, as that whence the principle of mutation, or permanency, or motion is derived. …It is, however, necessary always to investigate

the supreme cause of every thing …Further still, it is necessary to investigate the genera of genera; and the particulars of particulars… We should also explore the capacities of the capabilities, and the energizers of the things affected by energy.