existence. The influence of this force, moreover, extends from the parent to the offspring, generation after generation." This is the commonly received doctrine, that physical phenomena are to be referred to physical forces ; vital phenomena to vital force ; and mental phenomena to mind. The new doctrine, however, is that all phenomena are to be referred to physical forces, no other forces being either known or knowable.
The more advanced Opinions.
The second view adopted in reference to the relation of physical to vital force, is, that if there be any difference it cannot be known. Physical forces are known. They can be measui'ed. They can not only be converted one into another, but can be proved to be quan- titively equivalent. If any other kind of force be assumed to account for vital phenomena, the assumption is gratuitous. It is taking for granted that something exists of which we know, and can know nothing. It must, therefore, lie beyond the sphere of science and is of no importance. Even Dr. Carpenter uses such language, as this : " Another class of reasoners have cut the knot which they could not untie, by attributing all the actions of living bodies for which physics and chemistry cannot account, to a hypo- thetical ' vital principle ; ' a shadowy agency that does everything in its own way, but refuses to be made the subject of scientific ex- amination; like the ' od-force,' or the 'spiritual power' to which the lovers of the marvellous are so fond of attributing the mysterious movements of turning and tilting tables." ^ " If a man asks me," says Prof. Huxley, " what the politics of the inhabitants of the moon are, and I reply, that I do not know ; that neither I, nor any one else, have any means of knowing ; and that, under these cir- cumstances, I decline to trouble myself about the subject at all, I do not think he has any right to call me a skeptic." ^ It is thus he banishes vitality from the sphere of science, because everything, except matter and its functions, belongs to the region of the un- known and the unknowable. Prof. Tyndall and Herbert Spencer take, at times, the same ground.
But, although such writers as Dr. Carpenter, in apparent con- tradiction to their own admissions, acknowledge the existence of " a directing agency " in the living germ, the majority of the writers of this school refuse to recognize any such agency or force as a scientific truth. The only difference between the second and
1 Youmans, p. 402.
' " Physical Basis of Life" in his Lay Sermons, p. 158.
268 I ART L — THEOLOGY. fCn. HI. — Anti-Theism.
third views on this general suhject, above referred to, is, that ac- cording to the one, the assumption of vital as distinct from physical force, is regarded as gratuitous and unnecessary ; according to the other, any such assumption is declared to be unphilosophical, and to be utterly discarded. The same writer sometimes takes one, and sometimes the other of these grounds.
The Argument for the Correlation of Physical and Vital Forces. Thus Prof. Huxley, although a few years since a firm advocate of vital, as distinct from physical force, in his discourse on the " Physical Basis of Life," takes the opposite ground. The argu- ment is this : the elements furnished by the mineral kingdom are taken up by the plant, and, under the influence of light and heat, transformed into organized matter. The products of vegetation, starch, sugar, fibrine, etc., are purely material. This is true even of protoplasm, or living matter, or the physical basis of life, as it is called, which is elaborated by the plant out of the lifeless materials furnished by the soil and the atmosphere. There is indeed a great difference between the products of vegetation and the lifeless ele- ments out of which they are formed. But so there is between the elements of water and water itself. If an electric spark be passed through a volume of oxygen and hydrogen gas, it becomes water, which weighs precisely as much as the volume of the two gases of which it is composed. It is oxygen and hydrogen in combination, and nothing more. Yet the properties of the water are entirely different from those of the oxygen and hydrogen. In like manner there is a great difference between the properties of the carbonic acid, the water, and the ammonia, of which the plant is composed,* and the living plant itself. But as it would be unphilosophical to assume the existence of an unknown something called aquosity to account for the difference between water and its elements, it is no less unphilosophical to assume the existence of an unknown some- thing called vitality to account for the difference between it and the lifeless materials of which hving matter is composed.
Animal Life. In like manner all the phenomena of animal life are referred to the physical forces inseparable from the matter which composes the animal structure. It is true the functions of matter in the animal tissues are higher than in those of the plant. But the advocates of the theory under consideration, endeavor to reduce the differ- ence between animal and vegetable life to a minimum. It is only