It would be vain to touch upon a discussion so extended as this. In the first chapter I have remarked that the idea of cause does not enter into the conceptions of pure logic or thought. It is, as Hamilton saw, material. I shall only pause to show what is meant by the term “cause” in the physical sciences. When one event follows another, time after time, we have “uniformity of sequence.” Suppose the constitution of the race were so happy that we slept at night only, and always awoke a few moments before sunrise. Such a sequence quite without exception, should, if uniform experience is the source of the idea of cause, justly lead to the opinion that the sun rises because man awakes. As we know this conclusion would be erroneous, some other element beside sequence must complete a real cause. If now, it were shown that the relation of cause to effect which we actually entertain and cannot help entertaining is in some instances flatly contrary to all experience, then we must acknowledge that the idea of cause asks to confirm it something quite independent of experience, that is abstract. But such examples are common. We never saw two objects continue to approach without meeting; but we are constrained to believe that lines of certain descriptions can forever approach and never meet. The uniformity of sequence is, in fact, in the physical sciences never assumed to express the relation of cause and effect, until the connection between the antecedent and consequent can be set forth abstractly in mathematical formulæ. The sequence of the planetary motions was discovered by Kepler, but it was reserved for Newton to prove the theoretical necessity of this motion and establish its mathematical relations. The sequence of sensations to impressions is well known, but the law of the sequence remains the desideratum in psychology.[92-1] Science, therefore, has been correctly defined as “the knowledge of system.” Its aim is to ascertain the laws of phenomena, to define the “order in things.” Its fundamental postulate is that order exists, that all things are “lapped in universal law.” It acknowledges no exception, and it considers that all law is capable of final expression in quantity, in mathematical symbols. It is the manifest of reason, “whose unceasing endeavor is to banish the idea of Chance.”[93-1] We thus see that its postulate is the same as that of the religious sentiment. Wherein then do they differ? Not in the recognition of chance. Accident, chance, does not exist for the religious sense in any stage of its growth. Everywhere religion proclaims in the words of Dante:-- “le cose tutte quante, Hann’ ordine tra loro;” everywhere in the more optimistic faiths it holds this order, in the words of St. Augustine, to be one “most fair, of excellent things.”[93-2]