In the present work the order adopted is, Deduction in chaps.ii.to xiii.; Induction in chaps.xiii.to xx.; and, lastly, Classification.

But such divisions do not represent fundamentally distinct and opposed aspects of the science.

For although, in discussing any question with an opponent who makes admissions, it may be possible to combat his views with merely deductive arguments based upon his admissions; yet in any question of general truth, Induction and Deduction are mutually dependent and imply one another.
This may be seen in one of the above examples.

It was argued that a certain metal must be copper, because every metal is copper that turns green when dipped in vinegar.

So far the proof appealed to a general proposition, and was deductive.