No amount of argument could have been more effectual in supporting the claim for mutual toleration than those two speeches, and thenceforward such forms of criticism were conspicuous by their absence. And where honesty of conviction was patent, mutual toleration was often replaced by personal esteem and regard. "Charity, brotherly love," writes Huxley, "were the chief traits of the Society. We all expended so much charity, that, had it been money, we should every one have been bankrupt."
The special part played in the society by Huxley was to show that many of the axioms of current speculation are far from being axiomatic, and that dogmatic assertion on some of the cardinal points of metaphysic is unwarranted by the evidence of fact. To find these seeming axioms set aside as unproven, was, it appears from his "Life," disconcerting to such members of the society as Cardinal Manning, whose arguments depended on the unquestioned acceptance of them. It was no doubt the observation of a similar attitude of mind in Mr. Gladstone towards metaphysical problems which provoked Huxley to reply, when asked whether Mr. Gladstone was an expert metaphysician—"An expert in metaphysics? He does not know the meaning of the word."
In addition to his share in the discussions, Huxley contributed three papers to the society. The first, read November 17, 1869, was on "The views of Hume, Kant, and Whately on the logical basis of the doctrine of the Immortality of the Soul," showing that these thinkers agreed in holding that no such basis is given by reasoning, a part, for instance, from revelation. A summary of the argument appears in the essay on Hume ("Collected Essays" 6 201 sq.)
On November 8, 1870, he read a paper, "Has a Frog a Soul? and if so, of what Nature is that Soul?" Experiment shows that a frog deprived of consciousness and volition by the removal of the front part of its brain, will, under the action of various stimuli, perform many acts which can only be called purposive, such as moving to recover its balance when the board on which it stands is inclined, or scratching where it is made uncomfortable, or croaking when pressed in a particular spot. If its spinal cord be severed, the lower limbs, disconnected from the brain, will also perform actions of this kind. The question arises, Is the frog entirely a soulless automaton, performing all its actions directly in response to external stimuli, only more perfectly and with more delicate adjustment when its brain remains intact, or is its soul distributed along its spinal marrow, so that it can be divided into two parts independent of one another?
The professed metaphysician might perhaps tend to regard such consideration as irrelevant; but if the starting-point of metaphysics is to be found in psychology, psychology itself depends to no small extent upon physiology. This question, however, Huxley did not pretend to solve. In the existing state of knowledge he believed it to be insoluble. But he thought it was not without its bearing upon the supposed relations of soul and body in the human subject, and should serve to give pause to current theories on the matter.
His third paper, read January 11, 1876, was on the "Evidence of the Miracle of the Resurrection," in which he argued that there was no valid evidence of actual death having taken place. His rejection of the miraculous had led to an invitation from some of his opponents in the society to write a paper on a definite miracle, and explain his reasons for not accepting it. His choice of subject was due to two reasons: firstly, it was a cardinal instance; secondly, it was a miracle not worked by Christ Himself, and therefore a discussion of its genuineness could offer no suggestion of personal fraud, and hence would avoid inflicting gratuitous pain upon believers in it.
This certainty that there exist many questions at present insoluble, upon which it is intellectually, and indeed morally wrong to assert that we have real knowledge, had long been with him, but, although he had earned abundant odium by openly resisting the claims of dogmatic authority, he had not been compelled to define his philosophical position until he entered the Metaphysical Society. How he came to enrich the English language with the name "Agnostic" is explained in his article "Agnosticism" ("Collected Essays" 5 pages 237-239).
After describing how it came about that his mind] "steadily gravitated towards the conclusions of Hume and Kant," [so well stated by the latter as follows:—
The greatest and perhaps the sole use of all philosophy of pure reason is, after all, merely negative, since it serves not as an organon for the enlargement (of knowledge), but as a discipline for its delimitation; and, instead of discovering truth, has only the modest merit of preventing error:—
he proceeds:—]