We sum up what has been said in the preceding paragraphs on the uniformity of nature in the following words: We admit that the uniformity of the constitution of nature is a self-evident and necessary truth. We admit also that, so far as our experience extends, the uniformity of the course of nature must be admitted as a scientific truth, for to deny this would be to deny the possibility of all science, inasmuch as all science is prevision. But at the same time we maintain that the conclusions of scientific inference must always be of a hypothetical and purely provisional character, because it is impossible for us to judge with absolute certainty how far our experience gives us adequate information of the universe as a whole, and of all the forces and phenomena which can have place therein.[475] The conservation of energy, for example, is a very probable hypothesis which accords satisfactorily with the experiments of scientific men during a few years past, but it would be a gross misconception of the nature of scientific inference to suppose that it is certain in the same sense that a proposition in geometry is certain, or that any fact of immediate consciousness is certain.[476]
Admitting the principle of the uniformity of nature as a hypothetical inference from a limited experience, we advance to the main position of Dr. Tyndall, namely, that personal volition can not mingle in or interfere with the procession of phenomena in nature.
Dr. Tyndall admits the reality of "personal volition." We have not discovered in his writings any indications of the tendency manifested by some of his scientific associates to reduce volition to a form of physical energy. He grants "the power of free-will in man,"[477] but he seems unwilling to admit that free-will can exert any controlling, modifying, or determining influence on the procession of phenomena. "Assuming the efficacy of prayer to produce changes in external nature, it necessarily follows that natural laws are more or less at the mercy of man's volition, and no conclusion founded on the assumed permanence of those laws would be worthy of confidence."[478] But are not natural laws more or less subject to man's volition? Does he not act upon the chain of cause and effect in nature, and alter the procession of phenomena on earth? Certainly he can and does control and direct the forces of nature. He can so collocate and adjust the properties and forces of matter as to accomplish the purposes of his intelligence, and bring about new results which would not otherwise have been produced. That man has materially modified the physical geography of the globe can not be denied. He has altered the climatal condition of whole tracts of country, and changed the physiognomy of the globe. The rain-fall has been changed by the felling of timber or the planting of trees.[479] He has extended or circumscribed the geographical boundaries of plants and animals. He has learned to control the mechanical, chemical, and electric forces. When he lifts a stone from the earth and suspends it in the air, or locks it in the arch that spans the river, the law of gravitation is subordinated to the higher law of intelligent purpose. By the collocation and adjustment of mechanical forces he overcomes the resistance of winds and tides, and guides his vessel across the trackless deep. He seizes the lightning in the clouds and guides it harmless to the earth, and sends the electric current along the telegraphic wire to chronicle his deeds and report his thoughts at the ends of the earth. He loosens the most intricate combinations of elementary substances, and recomposes them in new forms of the highest value in medicine and the fine arts. He solidifies carbonic acid; freezes water at the tropics, and even in red-hot crucibles in the Temperate Zone. He also modifies and changes the development of vegetable life, obliterating thorns and spines, altering the color and size of flowers, and the flavor and nutritive character of fruits. And, finally, he has wrought marvelous changes in the form, size, habits, and instincts of the animal creation.[480] Thus in numberless ways does man control, modify, and subordinate nature to accomplish the purposes of his intelligence; but we can not see with Dr. Tyndall how this renders scientific "conclusions founded on the assumed permanence of natural law unworthy of confidence."
There is a vacillation in Dr. Tyndall's treatment of this aspect of the subject which renders it difficult to fix his exact position. Does he intend to assert that "personal volition" can not in the slightest degree change the succession of phenomena? Will he say that man does not, and that God can not control and modify and subordinate natural forces so as to bring about new and special results? Unless he is prepared to assert this in the most unequivocal manner, the whole superstructure of his argument falls to the ground. If it is granted that human volition can change the procession of phenomena, and "alter within certain limits the current of events," then à fortiori we may conclude that Divine volition may also interfere in the economy of nature to answer prayer. At one time Dr. Tyndall insinuates that "our notion" (that is, the Christian's conception) "of the Power which rules the universe" is a "mere fanciful or ignorant enlargement of human power,... a mythologic imagination which pictures a being able and willing to do any and every conceivable thing."[481] At another time he admits that "the theory that the system of nature is under the control of a Being who changes phenomena in compliance with the prayers of men is, in my opinion, a perfectly legitimate one.... It is a matter of experience that an earthly father, who is at the same time both wise and tender, listens to the requests of his children, and if they do not ask amiss, takes pleasure in granting their requests. We know also that this compliance extends to the alteration, within certain limits, of the current of events on earth. With this suggestion offered by our experience, it is no departure from scientific method to place behind natural phenomena a universal Father, who in answer to the prayers of his children alters the currents of phenomena. Thus far theology and science go hand in hand. The conception of an ether, for example, trembling with the waves of light, is suggested by the ordinary phenomena of wave-motion in water and in air; and in like manner the conception of personal volition in nature is suggested by the ordinary action of man upon earth. I therefore urge no impossibilities, though you constantly charge me with doing so. I do not even urge inconsistency, but, on the contrary, frankly admit that you have as good a right to place your conception at the root of phenomena as I have to place mine."[482]
If this concession is made in good faith, and really means any thing at all, it covers the whole ground. It is neither unscientific nor irrational to place behind natural phenomena a universal Father who alters the current of phenomena in answer to prayer. But this is not the conception which Dr. Tyndall places behind the phenomena of nature. His conception is that of a permanent force, which is "under the circumstances necessary," producing "an unerring order which in our experience knows no exception." This brings us to the third and last question.
3. How can the scientific conception of the force which is manifested in the phenomena of nature be brought into harmony with the idea of God as revealed in the religious consciousness?
We are now in the very heart of what we have characterized as the debatable ground which lies between science and religion, where questions are mooted concerning the relation between God and nature.
On the one side we have the facts of external sensible experience—the statical phenomena of nature as mass, extension, position, and distance—conditions essential to the action or manifestation of force; then the dynamical phenomena of nature as rotatory, vibratory, pulsatory, gyratory, and transitive motion, which to our reason, not to our senses, are manifestations of force. Science observes the uniformity of relations among these phenomena—uniformities of resemblance, co-existence, and succession, and calls these uniformities laws of nature. This is all that science can do, all that men of exact science claim to be able to do.
On the other side we have the facts of internal experience—the consciousness of effort, the sense of power and freedom, the idea of right and wrong, the feeling of dependence, of duty, and of obligation, the consciousness of moral responsibility and of moral desert, and the anticipation of a future retribution. These to our reason are the revelation of a righteous Lawgiver and Ruler who is over us; by whom we are obliged, and to whom we must account. This is the theoretic basis and necessary presupposition of all religion.