Belief, however, is a conviction of something which may or may not require what are called "scientific grounds" before we can be permitted to profess that we believe. It depends upon the thing which we profess to believe, and upon the grounds on which we rest the belief, whether we have or have not safe and sufficient means of belief. Belief in the law of gravitation as a force operating throughout the universe is arrived at as a deduction from scientific data. Belief in an existence beyond phenomena, in a being who is the producing agent of the phenomena, depends upon a great variety of grounds, some of which are scientific data and some of which are the elements of moral reasoning. We may not say that we "_know_" that God or any other supernatural being exists, but we may say that we "_believe_" in his existence. Here knowledge is one thing; belief is another. Knowledge of the existence of God, like knowledge of the existence of any other being, might come to us through the testimony of a competent witness commissioned and authorized to inform us. Belief in the existence of God may be founded on many and various grounds without the direct testimony of the competent witness; and these grounds may be perfectly satisfactory without being mathematical or scientific demonstration. It is a very remarkable fact that some of the most eminent of the school of agnosticism profess to have, and probably have, the most undoubting faith in the theory and actual occurrence of animal evolution, without any data, scientific or other, which can enable other men to arrive at the same conviction, whatever may be the character of the supposed proofs. They certainly have no grounds for professing to know that an evolution of species out of species has ever taken place; and the grounds of their belief in the fact, whether denominated "scientific" or called something else, do not satisfy the rules of belief on which mankind must act, in accordance with their mental and moral constitutions; and this belief does not rise any higher in the scale of moral probabilities than the belief in special creations, nor does it rise so high. But to return to Mr. Spencer.