Psychology Down the Ages

Spearman's central argument is that the history of psychology should be read as a progressive convergence toward the laws of noegenesis and the two-factor theory of intelligence that he himself formulated. The book rejects the assumption that psychology made no real scientific progress before the twentieth century, but it equally rejects the notion that progress consists in accumulating isolated findings. For Spearman, genuine advance means arriving at universal laws — of apprehension, eduction of relations and correlates, mental energy, retentivity, fatigue, and control — that can account for every form of knowing. The historical survey serves this thesis by showing that earlier thinkers were groping toward these laws without the mathematical tools to formulate them.

John A. McGeoch's review in Psychological Bulletin (1938) was sharply critical, observing that were one seeking evidence that history is a function of the historian, this book would serve as an excellent example. McGeoch noted that Spearman made no effort to show development in temporal sequence, instead painting the intellectual background of those aspects of modern psychology in which he was interested, and closing the second volume with chapters primarily on his own work. McGeoch described the book as oriented throughout toward the author's laws, with his work on 'G' and the specific factors. F. Aveling in Nature was more sympathetic, noting the immense acquaintance with psychological literature that must have been in the background of Spearman's mind throughout.

The organizing concept is noegenesis, Spearman's term for the three principles of knowledge origination: apprehension of experience, eduction of relations, and eduction of correlates. These principles, first systematically presented in The Nature of Intelligence and the Principles of Cognition (1923), are the qualitative laws that Spearman believed govern all cognitive activity. In Psychology Down the Ages, he uses noegenesis as the standard against which past doctrines are measured. Thinkers who recognized that knowledge involves more than association — that it requires the eduction of relations not given in the raw data — are treated as precursors. Associationism, which Spearman had spent decades attacking, is presented as the great historical obstacle to recognizing these principles.

The first volume is a historical survey studded with quotations from ancient, medieval, and modern sources, with references collected in notes at the end of the second volume. McGeoch observed that this copiousness of quotation, while promoting accuracy, was sometimes clumsy. The second volume shifts method: it becomes more direct exposition and freer from quotation, because its subject is Spearman's own and related work. The final chapters are primarily on his experimental program at University College London, including the quantitative laws of mental energy, retentivity, fatigue, and control. The forty-two chapters across both volumes are grouped in five parts: what psychology is about, what the psyche can do, how it is constituted, what follows what, and what goes with what.

Factor analysis is present as the methodological spine of the second volume but is not the subject of historical survey in the first. Spearman developed his two-factor theory through mathematical analysis of correlations among cognitive tests, and the book assumes familiarity with this work rather than re-deriving it. Aveling noted in Nature that by 1937 the most trenchant of Spearman's erstwhile critics had adopted his mathematical treatment of psychological data and were extending it to temperamental and character qualities. The book's historical argument depends on this methodological achievement: without the statistical apparatus to identify a general factor, the convergence thesis would lack its evidential base.

The book's neglect stems from its acknowledged partisanship. McGeoch's review made the problem explicit: the work is oriented throughout toward Spearman's own laws, and the second volume is a history of his own and related work. Later historians of psychology preferred surveys that at least attempted temporal sequence and balanced coverage. The book also appeared in 1937, as Spearman was approaching retirement, and its two-volume format made it impractical for classroom use. More fundamentally, Spearman's noegenetic laws and the two-factor theory, while foundational for psychometrics, never achieved the broad disciplinary consensus that would have sustained interest in a history written from their standpoint.