things and acts, generation after generation, may produce organic repugnance to such things and acts,[1] might, had it been known to him, have made him suspect that conscience is a product of Evolution. And in that case his conception of it would not have been incongruous with the facts above named, showing that there are widely different degrees of conscience in different races.
In brief, as already implied, had Kant, instead of his incongruous beliefs that the celestial bodies have had an evolutionary origin, but that the minds of living beings on them, or at least on one of them, have had a non-evolutionary origin, entertained the belief that both have arisen by Evolution, he would have been saved from the impossibilities of his Metaphysics, and the untenabilities of his Ethics. To the consideration of these last, let us now pass.
Before doing this, however, something must be said concerning abnormal reasoning as compared with normal reasoning.
Knowledge which is of the highest order in respect of certainty, and which we call exact science, is distinguished from other knowledge by its definitely quantitative previsions.[2] It sets out with data, and proceeds by steps, which, taken together, enable it to say under what specified conditions a specified relation of phenomena will be found; and to say in what place, or at what time, or in what quantity, or all of them, a certain effect will be witnessed. Given the factors of any arithmetical operation, and there is absolute certainty in the result reached, supposing there are no stumblings: stumblings which always admit of detection and disproof by the method which we shall presently find is pursued. Base and angles having been accurately measured, geometry yields with certainty the distance or the height of the object of which the position is sought. The ratio of the arms of a lever having been stated, mechanics tells us what weight at one end will balance an assigned weight at the other. And by the aid of these three exact sciences, the Calculus, Geometry, and Mechanics, Astronomy can predict to the minute, for each separate place on the Earth, when an eclipse will begin and end, and how near it will approach to totality. Knowledge of this order has infinite justifications in the successful guidance of infinitely numerous human actions. The accounts of every trader, the operations of every workshop, the navigation of every vessel, depend for their trustworthiness on these sciences. The method they pursue, therefore, verified in cases which pass all human power to enumerate, is a method not to be transcended in certainty.
What is this method? Whichever of these sciences we exam-
