There is no law, no principle, based on past practice, which may not be overthrown in a moment, by the arising of a new condition, or the invention of a new material; and the most rational, if not the only, mode of averting the danger of an utter dissolution of all that is systematic and consistent in our practice, or of ancient authority in our judgment, is to cease, for a little while, our endeavours to deal with the multiplying host of particular abuses, restraints, or requirements; and endeavour to determine, as the guides of every effort, some constant, general, and irrefragable laws of right — laws, which based upon man’s nature, not upon his knowledge, may possess so far the unchangeableness of the one, as that neither the increase nor imperfection of the other may be able to assault or invalidate them.