It was not to establish a thing so generally known that I wished to write a book; I had a newer and more important object.

This was to search for the causes of these variations, and, by confining my observations to those which depend on ourselves, to demonstrate in what manner it might be possible to direct them, in order to render us better and more certain of our dispositions.

For it is undoubtedly more painful to an honest man to resist desires already formed, and which it is his duty to subdue, than to prevent, change, or modify the same desires in their source, were he capable of tracing them to it.

A man under temptation resists once because he has strength of mind, he yields another time because this is overcome; had it been the same as before he would again have triumphed.
By examining within myself, and searching in others what could be the cause of these different manners of being, I discovered that, in a great measure they depended on the anterior impressions of external objects; and that, continually modified by our senses and organs, we, without knowing it, bore in our ideas, sentiments, and even actions, the effect of these modifications.

The striking and numerous observations I had collected were beyond all manner of dispute, and by their natural principle seemed proper to furnish an exterior regimen, which varied according to circumstances, might place and support the mind in the state most favorable to virtue.