Those only are happy (I thought) who have their minds fixed on some object other than their own happiness; on the happiness of others, on the improvement of mankind, even on some art or pursuit, followed not as a means, but as itself an ideal end.

Aiming thus at something else, they find happiness by the way.

The enjoyments of life (such was now my theory) are sufficient to make it a pleasant thing, when they are taken _en passant_, without being made a principal object.
Once make them so, and they are immediately felt to be insufficient.
They will not bear a scrutinizing examination.

Ask yourself whether you are happy, and you cease to be so.

The only chance is to treat, not happiness, but some end external to it, as the purpose of life.