Book 1
19
A carpenter and a geometrician both try to find a right angle,Or straight line. but in different ways; the former is content with that approximation to it which satisfies the purpose of his work; the latter, being a student of truth, seeks to find its essence or essential attributes. We should therefore proceed in the same manner in other subjects also, and not allow side issues to outbalance the main task in hand.
20
Nor again must we in all matters alike demand an explanation of the reason why things are what they are; in some cases it is enough if the fact that they are so is satisfactorily established.Cf. 4.7. This is the case with first principles; and the fact is the primary thing—it is a first principle.
21
And principles are studied—some by induction, others by perception, others by some form of habituation, and also others otherwiseThis is usually taken that is, different ones in different ways, but καὶ . . . δέ seems to refer to other classes as well.;
22
so we must endeavor to arrive at the principles of each kind in their natural manner, and must also be careful to define them correctly,
23
since they are of great importance for the subsequent course of the enquiry. The beginning is admittedly more than half of the whole,The usual form of the proverb is The beginning is half of the whole. Aristotle applies it by a sort of play on words to ἀρχή in its technical sense of a general principle of science, which is a beginning in the sense that it is the starting-point of deductive reasoning. There is a reminiscence of Hesiod, Hes. WD 30, πλέον ἥμισυ παντός, The half is more than the whole, though the meaning of that is entirely different. and throws light at once on many of the questions under investigation.
