The charge of Fatalism has accompanied every fresh extension of Positive science, from its first beginnings. Nor is this surprising; for when any series of phenomena passes from the dominion of Wills, whether modified by metaphysical abstractions or not, to the dominion of Laws, the regularity of the latter contrasts so strongly with the instability of the former, as to present an appearance of fatality, which nothing but a very careful examination of the real character of scientific truth can dissipate. And the error is the more likely to occur from the fact that our first types of natural laws are derived from the phenomena of the heavenly bodies. These, being wholly beyond our interference, always suggest the notion of absolute necessity, a notion which it is difficult to prevent from extending to more complex phenomena, as soon as they are brought within the reach of the Positive method. And it is quite true that Positivism holds the Order of Nature to be in its primary aspects strictly invariable. All variations, whether spontaneous or artificial, are only transient and of secondary import. The conception of unlimited variations would in fact be equivalent to the rejection of Law altogether. But while this accounts for the fact that every new Positive theory is accused of Fatalism, it is equally clear that blind persistence in the accusation shows a very shallow conception of what Positivism really is. For, unchangeable as the Order of Nature is in its main aspects, yet all phenomena, except those of Astronomy, admit of being modified in their secondary relations, and this the more as they are more complicated. The Positive spirit, when confined to the subjects of Mathematics and Astronomy, was inevitably fatalist; but this ceased to be the case when it extended to Physics and Chemistry, and especially to Biology, where the margin of variation is very considerable. Now that it embraces Social phenomena, the reproach, however it may have been once deserved, should be heard no longer, since these phenomena, which will for the future form its principal field, admit of larger modification than any others, and that chiefly by our own intervention. It is obvious then that Positivism, far from encouraging indolence, stimulates us to action, especially to social action, far more energetically than any Theological doctrine. It removes all groundless scruples, and prevents us from having recourse to chimeras. It encourages our efforts everywhere, except where they are manifestly useless. [The charge of Optimism applies to Theology rather than to Positivism. The positivist judges of all historical actions _relatively_, but does not justify them indiscriminately]