A final fact adduced against the theory that it is impossible to think without language, which was very popular, is that deaf and dumb people cannot speak, and yet can think; this argument has no great value, as it is now averred that “a man born dumb who had always lived among deaf and dumb people, and had not been taught to express thoughts by signs would be capable of few higher intellectual manifestations than a monkey or an elephant; and this in spite of the fact that no naturalist could distinguish any difference between the size of their brains and those belonging to men who could speak.” For deaf mutes to be able to think and reason, they must have learned from those who use words, then only can they substitute other signs for their words and concepts. Still Professor Huxley accords to these unfortunate men certain intellectual heritages derived from their parents. These are some of the chief points in the science of language. The fundamental law which this science lays down of the unity of thought and speech is a torch which may throw light on the origin of man. FOOTNOTES: [28] Max Müller says: “I use percept instead of presentation, because it is better understood in English.”--_Science of Thought_, p. 2. [29] Max Müller’s _Science of Thought_, p. 72. [30] _Ibid._, p. 17. [31] _Ibid._, p. 75. [32] _Science of Thought_, p. 30. CHAPTER IV ANIMALS Whilst philosophers and moralists have studied men, and naturalists animals, Darwin considered it necessary to collect information concerning both men and beasts simultaneously before making a biography of the human being. With the modesty so often characteristic of a great genius, the English naturalist acknowledges that “many of the views which have been advanced are highly speculative, and some no doubt will prove erroneous. False facts are highly injurious to the progress of science, for they often long endure; but false views, if supported by some evidence, do little harm, as everyone takes a salutary pleasure in proving their falseness; and when this is done, one path towards error is closed and the road to truth is often at the same time opened.”[33] Although there is no doubt that the facts observed by Darwin and recorded in the _Origin of Species_, are perfectly correct, I hope to be able to dispose of the opinion that “man and animals follow parallel lines in their lives, but that man advances more quickly, and has taken his place in the front rank.” Whilst making a short _résumé_ of remarks which Noiré and other learned writers have made on animals, I also propose to draw a comparison between the two who are so closely connected--the superior and inferior animal.