There is scarcely a faculty man possesses, which is not immeasurably limited in comparison with the powers and capabilities of inanimate nature. His physical energy, when compared with that of the
momentum of this Earth, is so exceedingly small that it can hardly be conveyed to our minds by means of figures; even the steam engine, excessively wasteful as it is of power, far surpasses him in strength. The duration of his existence is to that of the world he inhabits, as nothing to infinity. His power and speed of locomotion are also very limited; the globe to which he is fixed by gravity, moves in one hour through a distance greater than he could walk in twenty years. Practically, by circumstances, he is almost rooted like a vegetable to the locality where he exists; comparatively few men have walked even a hundred miles from their homes, or have been conveyed round this little globe by the aid of all our improved means of transport. A balloon can ascend in the air, but a man cannot; without the aid of that apparatus he is absolutely fixed to the surface of the Earth, and with the assistance of all the appliances of science, he cannot yet ascend even ten miles into the atmosphere, nor dive more than a few fathoms into the sea. His senses are equally contracted; his perceptions of touch and sound are far less delicate than that of the microphone; a photographic surface will detect vibrations of light which he cannot at all perceive, and record images more quickly than his brain; and for the detection of magnetism and the chemical rays of light he possesses no sense whatever:—electrometers and galvanometers can detect thousands of times smaller quantities of electricity than he can perceive:—whilst a bolometer renders manifest a one
hundred-thousandth of a Centigrade degree change of temperature, he can hardly detect a difference of an entire degree; and whilst carbon and platinum may be heated to whiteness without material change, a rise or fall of about five Fahrenheit degrees in his temperature endangers his life. His mental and intellectual powers are as limited as his senses; he can hardly reckon without making an error even a single million, nor can he conceive an adequate idea of a billion; a million miles or a millionth of an inch are each quite beyond his immediate perception; an extremely minute circumstance also is capable of disturbing and entirely diverting his train of thought. He cannot create or destroy even a particle of dust, nor form out of nothing a single idea. The velocity of transmission of his nervous power, and the speed of his execution of will, are also extremely slow in comparison with that of an electric current in a copper wire. Every person is aware that he can only very slowly receive and understand a new idea. His mental advance is as tardy as his locomotion, a sixth part of his life is spent in acquiring the merest rudiments of universal knowledge. Whilst his reasoning power, when applied to actual and truthfully stated experience, is truly "the great guide" of his life, it only renders explicit what was already contained in that experience; for when he draws an inference, he usually only states in one form of words, what he has already implicitly included in the propositions; and if the inference contains more than this it is
unwarranted. His mental helplessness in the absence of knowledge, is equal to his physical incapacity in the absence of light. Nearly every problem of nature also is so complex, and affected by so many conditions, that his reasoning power only enables him to advance a very minute step at a time in the discovery of new knowledge; he is then obliged to halt, and have recourse to new experiences obtained either by means of experiment and observation, or by the latter alone.
Man's moral actions are largely the effect of circumstances; his thoughts and actions are probably the whole of them limited by law. He is never free from the influence of causation. His mental and moral freedom are limited by the epoch in which he lives, by the customs of his nation, by the individuals by whom he is immediately surrounded, by the alcoholic stimulants of which he partakes, and by his own physical and mental constitution, his degree of intelligence, &c., &c. Whether he is willing or not, he is incessantly compelled to receive sensuous and mental impressions, and be influenced by an almost infinite number and variety of agencies acting upon him both from within and without:—To be mentally and physically active, and perform all the bodily functions and acts necessary to his existence:—To live on this globe in presence of all its phenomena, and be carried through space at an immense velocity:—To undergo through a long series of generations a progressive existence and development of civilization, &c., &c.
He is more subject to the laws of the Universe than those laws are subject to him; and he can only exercise his will successfully and become their master by first obeying them.
Under the influence of the light and heat of the Sun, the entire population of this planet (about fifteen hundred millions) are renewed out of the crust of the Earth every few years, by breathing the air, drinking the water, feeding upon plants which take their constituents from the Earth, water and air; or by eating animals which have lived upon plants; and if that heat and light, or that supply of food and air, were to cease, all those human beings would die, and all the moral phenomena of man on this globe would terminate. Whilst man cannot exist without the support of inanimate nature and the operation of its laws, inanimate nature and its laws can exist without him. That also which is naturally ordained by Creative power to be dependent, cannot be essentially more important than that upon which it depends for its existence. The essential importance of man in relation to the Universe, exists only in his own imagination.
These facts shew that the principles of science, and the physical and chemical properties of substances, lie at the very basis of man's existence and activity and it would therefore be incorrect to say that the physical system of the Universe is unimportant in comparison with the moral phenomena of mankind.
That science conduces to humanity by preventing
and alleviating animal suffering has been already alluded to (p. [80]-[81]). True humanity consists not in the abolition of experiments upon living creatures, but in the judicious employment of them. Instead of barbarously treating our suffering fellow creatures by indolently and ignorantly allowing causes of disease and pain to continually occur and take their course, it urgently enforces upon us the duty of extending our knowledge of physiology by means of new experiments, observations and study. It would be untruthful to say that experiments purposely made upon men and other animals do not yield new and valuable information;—Pharmacopœias and Materia-Medicæs are full of descriptions of the properties of curative agents discovered by these and other scientific methods.