bryonic life may be interpreted as a kind of "logical growth" or the development of a plan. The difficulty with this interpretation, again, is that it is merely formal and means nothing. If a Divine plan is to be invoked on every occasion as the explanation of whatever is obscure, all rational inquiry is at an end. God is not bound to give reasons. His ways are past finding out. Nature's ways, on the other hand, do lend themselves to progressive interpretation. There are ultimate questions that always elude us, but we can learn through experience and observation to connect cause and effect, antecedent and consequent. It is upon this line that the scientific investigators of the day are working; and not a day passes without bearing witness to the fruitfulness of their methods. This is the reason why, among scientific workers, an hypothesis that lends itself to verification, that deals with the actual and real, is always preferred to one that supplies a formula and nothing more.
We pass over, as containing little or nothing that is relevant to the subject of evolution, Dr. Porter's discussion of the doctrine of the conservation of energy. The next section of the lecture deals with the theory that the phenomena of life may be highly specialized and complicated forms of mechanical (molecular) action. "To put forward such a theory," says Dr. Porter, "is to hypostatize an agency or an agent of the vaguest and most nebulous character, and to claim for it all the attributes of things or agents that are known to exist under the severest tests of observation and experiment." We wish Dr. Porter would explain how it is possible to hypostatize an agent of the most nebulous character and yet assign to it a most definite character. The theory under consideration simply proceeds upon the principle that to simplify or explain you must generalize—that is to say, you must find the means of expressing the special in terms of the general. The phenomena of life are highly special phenomena, and we are naturally led to wish to see them in wider relations. To rest in the special is to rest in nescience; and the awakened human mind does not consent to that. The widest relations of all are those which we call mechanical; the natural tendency of thought, therefore, is toward the belief that it is through the compounding and recompounding of these, in ways and regions at present far beyond our ken, that matter acquires its higher and more specialized functions. We see in the human body what a mere aggregation of cells may become; we see in human society what a mere aggregation of individuals may become; and it is impossible that Science should not seek her equilibrium in some theory of the essential unity of all forms of matter and all modes of force. We must, however, quote a powerful sentence which in the lecture before us immediately follows (page 15) the words last quoted: "To apply induction to a process which ought to begin with analogy and end with fact, but which begins with a surmise and ends with a dogma, is to reverse the order and to deny the criteria which have given Science
