"Natural laws" and "second causes" are thus established by experience, and explicitly recognized in Scripture. It is necessary, however, especially with reference to certain modern speculations, to discriminate between the two; and to show that while they are closely related and equally legitimate objects of philosophical inquiry, they are nevertheless radically different, as well as easily distinguishable, from each other. It is the favorite doctrine of the Positive school in France that the knowledge of "causes" is utterly interdicted to man, and that the only science to which he should aspire consists exclusively in the knowledge of "phenomena," and their cooerdination under "general laws." M. Comte explicitly avows this doctrine, and Mr. Mill and Mr. Lewes give it their implied sanction.[189] According to their theory, all Science is limited to "the laws of the coexistence and succession of phenomena," and "causes" are not only unknown, but incapable of being known. And to such an extent is this doctrine carried that M. Comte anticipates the possible ultimate reduction of _all_ "phenomena" to _one_ all-comprehensive, all-pervading "law," as the highest perfection of Science and the decisive extinction of Religion; while Mr. Mill, doubtful of this being possible, thinks it conceivable, at least, that there may be worlds, different from our own, in which events occur _without causes_ of any kind, and even without any _fixed law_. In regard to this theory it might well be asked, how it comes to pass that human language, which is the natural exponent of human thought, should contain, in every one of its multifarious dialects, so many expressions which denote or imply "causation," if it be true that all knowledge of causes is utterly inaccessible to the human faculties? Nay, why is it that the axiom of causation needs only to be announced to command the immediate assent of the whole human race?