By far the most valuable things, which we know or can imagine, are certain states of consciousness, which may roughly be described as the pleasures of human intercourse and the enjoyment of beautiful objects. No one, probably, who has asked himself the question, has ever doubted that personal affection and the appreciation of what is beautiful in Art or Nature, are good in themselves; nor, if we consider strictly what things are worth having purely for their own sakes, does it appear probable that any one will think that anything else has nearly so much value as the things which are included under these two heads.

The study of Ethics would, no doubt, be far more simple, and its results far more "systematic," if, for instance, pain were an evil of exactly the same magnitude as pleasure is a good; but we have no reason whatever to assume that the Universe is such that ethical truths must display this kind of symmetry ... .

I can prove now, for instance, that two human hands exist. How? By holding up my two hands, and saying, as I make a certain gesture with the right hand, "Here is one hand," and adding, as I make a certain gesture with the left, "and here is another." And if, by doing this, I have proved ipso facto the existence of external things, you will all see that I can also do it now in numbers of other ways: there is no need to multiply examples.