Few circumstances connected with the discovery of new truths of science, have had a greater moral effect, than the very high degree of certainty of such truths. The moral result of this is a corresponding degree of confidence in the statements of science. Trustworthiness is a great moral quality. Uncertainty is a continual hindrance to action and enjoyment; and many persons are driven to believe in error, and hence to commit sin, rather than remain in suspense. Contradictions of doctrine, and the consequent uncertainty of belief, in any subject, are fertile sources of strife. Science consists, not merely of opinions and words, but also of the tangible realities which those opinions and words represent, the forces, substances and phenomena of the material Universe. Some persons however fancy that the results of science are as uncertain as those of the undemonstrable subjects with which they are familiar. Another way in which science has contributed to moral progress, has been by requiring greater accuracy in nearly all human actions, and thereby diffusing greater exactitude of language and of conduct, which has spread itself throughout all civilised society. Previous to the use of watches and clocks, persons were no doubt much less exact in fulfilling their appointments; the establishment also in our chief towns, of electric time-keepers regulated from Greenwich Observatory, is increasing exactitude in our large communities. Since the introduction of railways, millions of persons have been compelled to be more {138} exact in their movements, by the risk they incur of missing their train. Numerous inventions and processes based upon scientific discoveries could not be worked at all unless men possessed habits of greater accuracy than formerly. Workmen now require higher moral and intellectual education, and their duties require more intelligence and involve greater responsibility. Science diminishes error, and the avoidance of error is a large step towards the attainment of truth. There is no tyranny equal to that of false ideas. Error often produces immoral acts, and every act of immorality is a mental error. "The ignorant justice-loving man, enamoured of the right, is blinded by the speciousness of wrong." "Inaccuracy of thought is the cause not only of the errors we meet with in the sciences, but also of the majority of the offences which are committed in civil life,--of unjust quarrels, unfounded law suits, rash counsel, and ill-arranged undertakings. There are few of those which have not their origin in some error, and in some fault of judgment, so that there is no defect which it more concerns us to correct."[17]