Whilst also the novelty of the practical effects of new scientific truths in inventions, astonish persons in general; the definiteness of scientific phenomena, and the certainty with which they may be reproduced convince all competent persons who examine them, that they are rigidly subject to definite laws. In this way the antique belief that natural phenomena are produced by supernatural agencies, is gradually being abandoned, and the more moral conviction of the omnipresence and universality of law has been largely established in its stead. Every new scientific fact and invention thus becomes a new proof of the universality of law. Belief in the supernatural has diminished in proportion as scientific knowledge has advanced; instead of natural phenomena being erroneously ascribed to demons, spirits, supernatural {125} powers, and occult causes, they have been proved to be results of natural powers, acting in accordance with known principles. Assertions which have been made, that "the will is a supernatural power, independent of natural law" &c., are not supported by evidence at all equal in cogency to that in proof of the statement, that our mental and moral powers as a whole act in accordance with the great principles of science. That moral phenomena, like those of the physical sciences, are capable of being made the subject of experiment, observation, comparison, analysis, and inference, is very manifest. Every case of bribery may be viewed as an experiment in morality. The very common case where an employer tests the honesty of a servant by some contrivance, is also a trial of a similar kind. The dependence of the moral powers upon scientific conditions, is clearly seen in the influences of intoxicating drinks. A mere natural substance could not possibly overcome the influence of a power which exists entirely independent of it; _i.e._, a "supernatural" one. Even the greatest believer in the "supernatural" power of the human will, deplores the serious injury which the abuse of alcoholic liquors produces upon mankind, rendering the will powerless, and debasing the moral sentiments. The effects of opium, haschisch, &c., are other examples. A vast number of experiments remain to be made of the effects of drugs and organic compounds, both solid, liquid and gaseous, upon moral actions; {126} which will probably prove a still greater degree of dependence of those actions upon purely physical and chemical conditions.