It is a commonplace among moralists that you cannot get happiness by pursuing it. This is only true if you pursue it unwisely. Gamblers at Monte Carlo are pursuing money, and most of them lose it instead, but there are other ways of pursuing money, which often succeed. So it is with happiness. If you pursue it by means of drink, you are forgetting the hang-over. Epicurus pursued it by living only in congenial society and eating only dry bread, supplemented by a little cheese on feast days. His method proved successful in his case, but he was a valetudinarian, and most people would need something more vigorous. For most people, the pursuit of happiness, unless supplemented in various ways, is too abstract and theoretical to be adequate as a personal rule of life. But I think that whatever personal rule of life you may choose it should not, except in rare and heroic cases, be incompatible with happiness.
There are a great many people who have all the material conditions of happiness, i.e. health and a sufficient income, and who, nevertheless, are profoundly unhappy. In such cases it would seem as if the fault must lie with a wrong theory as to how to live. In one sense, we may say that any theory as to how to live is wrong. We imagine ourselves more different from the animals than we are. Animals live on impulse, and are happy as long as external conditions are favorable. If you have a cat it will enjoy life if it has food and warmth and opportunities for an occasional night on the tiles. Your needs are more complex than those of your cat, but they still have their basis in instinct. In civilized societies, especially in English-speaking societies, this is too apt to be forgotten. People propose to themselves some one paramount objective, and restrain all impulses that do not minister to it. A businessman may be so anxious to grow rich that to this end he sacrifices health and private affections. When at last he has become rich, no pleasure remains to him except harrying other people by exhortations to imitate his noble example. Many rich ladies, although nature has not endowed them with any spontaneous pleasure in literature or art, decide to be thought cultured, and spend boring hours learning the right thing to say about fashionable new books that are written to give delight, not to afford opportunities for dusty snobbism.