When law rigidly acts, the equations of dynamics show that the variety in the result is precisely the variety in the conditions, and no more. But just as all observations of the results, however nice they may be, will be affected with errors, so we may suppose that in the facts themselves there are excessively smaller and yet existent variations from the regularity that the law calls for. If this occurs continually, it may be ever so minute and yet in billions of years may produce varieties. This is the cosmological and metaphysical hypothesis which, in articles of years gone by, I called tychism.