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New Truth, and its General Relation to Human Progress.
The great source of the success of applying science to trade, and of the beneficent effect of science upon human welfare in general, is simply the influence of demonstrable truth. We know that if we have once discovered all the principles, laws, and conditions of some scientific phenomenon, or of some improved process or result in a manufacture, the reproduction of exactly the same conditions will hereafter enable us to invariably produce the same result. In this respect science differs from dogma, the truth or falsity of which cannot be demonstrated; it also differs from empiricism, because when empirically working a process we are ignorant of the principles or laws which are operating, whilst with a scientific knowledge we understand those laws, and can direct them to our particular purposes. In the process of electro-plating for example, we understand the laws of the phenomena, and can direct them so as to obtain silver of a hard or soft quality, brittle or tough, crystalline silver, &c., according to our wish; but if we had only an empirical knowledge of the subject we could not thus vary the process.
The highest test of truth is verified prediction; if we calculate beforehand that an eclipse of the Sun will occur at a certain hour and minute, and that eclipse occurs accurately at the predicted moment, we may rest assured that our knowledge upon that point is true and complete. If we say that a piece of clean iron, immersed in a solution of blue vitriol, will become covered with a layer of metallic copper, and we find upon trial that this result invariably occurs when we fulfil those conditions, we may be certain that our knowledge of this phenomenon and its conditions is also of a definite and certain character. Similarly, when we become able to predict with certainty the conditions of the Sun's surface, we shall probably also be able to predict severe winters, famines, &c., and therefore be prepared to suggest precautions to be taken against them. Even now the new truth necessary for this purpose is beginning to be evolved by means of scientific research.[[20]]
Amongst the great axioms and principles of science, possessing great certainty, and which enable us to predict, are, 1st. the general truth known as the Principle of Causation, that every effect has a cause; that the same cause, acting under the same conditions, always produces the same effect; and that causation acts through all time and all space:—2nd. the great truth, that every phenomenon requires time; and every substance occupies space:—3rd. the Principles of Conservation and Persistency of Matter
and Energy; that out of nothing, nothing comes; and out of everything, everything proceeds; that all the future states of the Universe are implicitly contained in and will be evolved out of the present state of the Universe; that we have no experience and possess no verified knowledge either of creation or annihilation of Matter or Energy; that we cannot absolutely create or destroy even an idea;[[21]] and that Matter and Energy appear to be eternal:—4th. the Principle of Convertibility and Equivalency of the different forms of Energy, according to which the various forces known as mechanical power, heat, light, electricity, magnetism, chemical action, &c., being modes of motion, are convertible into each other in equivalent quantities and without addition or loss. These and other great principles constitute the basis of physical and chemical science, by obeying which, we have been enabled to evolve all the wonderful practical realities of science of the present day.[[22]] To these great principles may be added the more concrete truth called the "Law of Progress," the essential idea of which is time, a time-rate; which regulates the speed of increase of civilization, and is evidently connected with the great truth that every phenomenon occupies time.
The Principle of Gravitation, demonstrated by Newton, explains a vast number of facts relating to the motions of the Heavenly bodies:—the
Undulatory Theory of Light, largely developed by the labours of Fresnel, renders equally clear and systematic an almost endless number and variety of optical phenomena; Oersted's law of Electro-magnetism similarly explains and renders consistent a multitude of facts respecting the movements of magnets and electric conductors, which would otherwise be confusing to remember and impossible to satisfactorily explain. And the great mental value of these comprehensive ideas to mankind, consists largely in relieving the memory and diminishing mental confusion, by co-ordinating a large number of different facts and apparently inconsistent phenomena by means of a general conception which embraces the whole of them. Thus a knowledge of the Principle of Gravitation informs us that both the ascent of a balloon in the air, and the descent of a stone in water, are alike due to the same force of gravity; and that of Chemical Affinity proves to us that the apparently unlike phenomena of slow rusting of iron and vivid combustion of phosphorus are essentially alike and due to the same cause.
All bodies, whether living or dead, and all forms of energy, appear to be absolutely subject to the great laws of Causation, Progress, Conservation, &c., no one can escape them; the man who transgresses the Law of Progress by being too much in advance of his epoch, is punished as certainly as he who lags behind it; all must advance together, and at approximately the prescribed rates.