It is astonishing how much the word infinitely is misused: everything is infinitely more beautiful, infinitely better, etc. The concept must have something pleasing about it, or its misuse could not have become so general.

You can make a good living from soothsaying but not from truthsaying.

Just as we outgrow a pair of trousers, we outgrow acquaintances, libraries, principles, etc., at times before they're worn out and times - and this is the worst of all - before we have new ones.

Do not judge God's world from your own. Trim your own hedge as you wish and plant your flowers in the patterns you can understand, but do not judge the garden of nature from your little window box.

The more experiences and experiments accumulate in the exploration of nature, the more precarious the theories become. But it is not always good to discard them immediately on this account. For every hypothesis which once was sound was useful for thinking of previous phenomena in the proper interrelations and for keeping them in context. We ought to set down contradictory experiences separately, until enough have accumulated to make building a new structure worthwhile.

Nothing is more conducive to peace of mind than not having any opinion at all.

Above all things expand the frontiers of science: without this the rest counts for nothing.