It is inevitable that we should take up at first borrowed principles; and unless we have all the faculties and the means of searching into their foundations, we naturally go on to the end as we have begun.
In the following chapter (IV.), he argues the general question of Innate Ideas in the case of the Idea of God.
In Book II., Chap.XXI., Locke discusses the freedom of the will, with some allusions to the nature of happiness and the causes of wrong conduct.

Happiness is the utmost pleasure we are capable of, misery the utmost pain; pleasure and pain define Good and Evil.

In practice, we are chiefly occupied in getting rid of troubles; absent good does not much move us.

All uneasiness being removed, a moderate portion of good contents us; and some few degrees of pleasure in a succession of ordinary enjoyments are enough to make happiness.

[Epicurus, and others among the ancients, said as much.] Men have wrong desires, and do wrong acts, but it is from wrong judgments.