Now, without at all doubting the important part which originally meaningless sounds may have played in furnishing material for vocal sign-making, and still less disputing the agency of association in the matter, I must nevertheless refuse to accept the above hypothesis as anything like a full explanation of the origin of speech. For it manifestly ignores the whole problem which stands to be solved—namely, the genesis of those powers of ideation which first put a soul of meaning into the previously insignificant sounds. Nearly all the warm-blooded animals so far share with mankind the same physiological nature as to give forth a variety of vocal sounds under as great a variety of mental states. Therefore, if in accordance with the above hypothesis we regard all such sounds as meaningless (or arising from the “purely physiological basis” of reflex movement), the question obviously presents itself, Why have not the lower animals developed speech? According to the above doctrine, aboriginal and hitherto speechless man started without any superiority in respect of the sign-making faculty, and thus far precisely resembled what is taken to be the present psychological condition of the lower animals.[303] Why, then, out of the same original conditions has there arisen so enormous a difference of result? If, in the case of mankind, associations of meaningless sounds with particular states, objects, &c., led to a substitution of the former for the latter, and thus gave to them the significance of names, how are we to account for the total absence of any such development in brutes? To me it appears that this is clearly an unanswerable difficulty; and therefore I do not wonder that the so-called interjectional theory of the origin of speech has brought discredit on the whole philosophy of the subject. But, as so often happens in philosophical writings, we have here a case where an important truth is damaged by imperfect or erroneous presentation. All the principles set forth in the above hypothesis are sound in themselves, but the premiss from which they start is untrue. This premiss is, that aboriginal man presented no rudiments of the sign-making faculty—that this faculty itself required to be originated _de novo_ by accidental associations of sounds with things. But, as we now well know from all the facts previously given, even the lower animals present the sign-making faculty in no mean degree of development; and, therefore, it is perfectly certain that the “Urmenschen,” at the time when they were “sprachlosen,” were not on this account _zeichenlosen_. The psychological germ of communication, which probably could not have been created by merely accidental associations between sounds and things, must already have been given in those psychological conditions of receptual ideation which are common to all intelligent animals.