In now carrying my study of mental evolution into the province of human psychology, it is desirable that I should say a few words to indicate the scope and intention of this the major portion of my work. For it is evident that “Mental Evolution in Man” is a subject comprehending so enormous a field that, unless some lines of limitation are drawn within which its discussion is to be confined, no one writer could presume to deal with it.

The lines, then, which I have laid down for my own guidance are these. My object is to seek for the principles and causes of mental evolution in man, first as regards the origin of human faculty, and next as regards the several main branches into which faculties distinctively human afterwards ramified and developed. In order as far as possible to gain this object, it has appeared to me desirable to take large or general views, both of the main trunk itself, and also of its sundry branches. Therefore I have throughout avoided the temptation of following any of the branches into their smaller ramifications, or of going into the details of progressive development. These, I have felt, are matters to be dealt with by others who are severally better qualified for the task, whether their special studies have reference to language, archÆology, technicology, science, literature, art, politics, morals, or religion. But, in so far as I shall subsequently have to deal with these subjects, I will do so with the purpose of arriving at general principles bearing upon mental evolution, rather than with that of collecting facts or opinions for the sake of their intrinsic interest from a purely historical point of view.

Finding that the labour required for the investigation, even as thus limited, is much greater than I originally anticipated, it appears to me undesirable to delay publication until the whole shall have been completed. I have therefore decided to publish the treatise in successive instalments, of which the present constitutes the first. As indicated by the title, it is concerned exclusively with the Origin of Human Faculty. Future instalments will deal with the Intellect, Emotions, Volition, Morals, and Religion. It will, however, be several years before I shall be in a position to publish these succeeding instalments, notwithstanding that some of them are already far advanced.

Touching the present instalment, it is only needful to remark that from a controversial point of view it is, perhaps, the most important. If once the genesis of conceptual thought from non-conceptual antecedents be rendered apparent, the great majority of competent readers at the present time would be prepared to allow that the psychological barrier between the brute and the man is shown to have been overcome. Consequently, I have allotted what might otherwise appear to be a disproportionate amount of space to my consideration of this the origin of human faculty—disproportionate, I mean, as compared with what has afterwards to be said touching the development of human faculty in its several branches already named. Moreover, in the present treatise I shall be concerned chiefly with the psychology of my subject—reserving for my next instalment a full consideration of the light which has been shed on the mental and social condition of early man by the study of his own remains on the one hand, and of existing savages on the other. Even as thus restricted, however, the subject-matter of the present treatise will be found more extensive than most persons would have been prepared to expect. For it does not appear to me that this subject-matter has hitherto received at the hands of psychologists any approach to the amount of analysis of which it is susceptible, and to which—in view of the general theory of evolution—it is unquestionably entitled. But I have everywhere endeavoured to avoid undue prolixity, trusting that the intelligence of any one who is likely to read the book will be able to appreciate the significance of important points, without the need of expatiation on the part of the writer. The only places, therefore, where I feel that I may be fairly open to the charge of unnecessary reiteration, are those in which I am endeavouring to render fully intelligible the newer features of my analysis. But even here I do not anticipate that readers of any class will complain of the efforts which are thus made to assist their understanding of a somewhat complicated matter.

As no one has previously gone into this matter, I have found myself obliged to coin a certain number of new terms, for the purpose at once of avoiding continuous circumlocution, and of rendering aid to the analytic inquiry. For my own part I regret this necessity, and therefore have not resorted to it save where I have found the force of circumstances imperative. In the result, I do not think that adverse criticism is likely to fasten upon any of these new terms as needless for the purposes of my inquiry. Every worker is free to choose his own instruments; and when none are ready-made to suit his requirements, he has no alternative but to fashion those which may.

To any one who already accepts the general theory of evolution as applied to the human mind, it may well appear that the present instalment of my work is needlessly elaborate. Now, I can quite sympathize with any evolutionist who may thus feel that I have brought steam-engines to break butterflies; but I must ask such a man to remember two things. First, that plain and obvious as the truth may seem to him, it is nevertheless a truth that is very far from having received general recognition, even among more intelligent members of the community: seeing, therefore, of how much importance it is to establish this truth as an integral part of the doctrine of descent, I cannot think that either time or energy is wasted in a serious endeavour to do so, even though to minds already persuaded it may seem unnecessary to have slain our opponents in a manner quite so mercilessly minute. Secondly, I must ask these friendly critics to take note that, although the discussion has everywhere been thrown into the form of an answer to objections, it really has a much wider scope: it aims not only at an overthrow of adversaries, but also, and even more, at an exposition of the principles which have probably been concerned in the “Origin of Human Faculty.”

The Diagram which is reproduced from my previous work on “Mental Evolution in Animals,” and which serves to represent the leading features of psychogenesis throughout the animal kingdom, will reappear also in succeeding instalments of the work, when it will be continued so as to represent the principal stages of “Mental Evolution in Man.”

18, Cornwall Terrace, Regent’s Park,
July, 1888.