(2) Further, the question to be determined may be presented as a problem in physiology, to be resolved by corresponding rules: What is the _function_ of certain parts of our human constitution, viz., the Reason and the Moral Faculty? Now it is a recognized principle that, in estimating function, you must study the organ, not in its rudimentary condition, before it has disengaged itself from adjacent admixtures and flung off the foreign elements, but in its perfect or differentiated state, so as to do its own work and nothing else. In order to give the idea of a timepiece to one who had it not, you would not send him to one of the curious mediæval clocks which could play a tune, and fire a gun, and announce the sunrise, and mark the tides, and report twenty miscellaneous things besides; but to the modern chronometer, simple and complete, that, telling only the moment, tells it perfectly. And in natural organizations, to learn the capabilities and project of any structure, you would not resort to the embryo where it is forming but not working: you would wait till it was born into the full presence of the elements with which it had to deal; not till then could you see how they played upon it, and what was its response to them. In conformity with this rule, whither would you betake yourself, if you want to measure the intrinsic competency of our intellectual faculty, and determine what its very nature gives it to know? Would you take counsel of the nurse who held you "when you first opened your eyes to the light,"[10] or otherwise study "the first consciousness in any infant," "before the time when memory commences,"[11] and disregard every thing "subsequent to the first beginnings of intellectual life"?[12] On the contrary, you would avoid that soft inchoate promise of nature, only nominally born, where the very structures of its finer work have not yet set into their distinctive consistency and form; and will hold your peace till the faculty is awake and on its feet, and can clearly tell you what it sees for itself, and what it makes out at second-hand: just as, to gauge the lunar light, you must have patience while the thin crescent grows, and wait till the full orb is there. Still less can you take the report of the Moral Faculty from the confessions of the cradle, or from the quarrels and affections of the apes; the conditions being not yet present for the bare conception of a moral problem. The most that can be asked of an intuition is, that it shall keep pace with the cases as they arise, and be on the spot when it is wanted; and if you would know what provision our nature holds for dealing with its Duty and interpreting its guilt, you must go into the thick of its moral life, and bid it tell you what it sees from the swaying tides of temptation and of victory. The "purity" of intuitions is not "pristine," but ultimate; cleared at length from accidental and irrelevant dilutions,