THE present volume was projected in December 1916, and the work upon it has been carried forward since then by conferences and correspondence. All of the essays here gathered were written specifically for it, and most of them have been redrafted several times during the progress of the discussion. The actual publication has been delayed, however, by the war work of one of the members of the group. Our belief in the value of co-operative effort has been fully justified to our own minds by the result; for while the doctrine as here presented is, by contrast with the other well-known views, essentially that which all the members of the group have held for some years past, its final expression has been greatly clarified and its analysis sharpened by the elaborate mutual criticism to which our papers have been subjected.

Especial credit should be given to Professor Strong and Professor Santayana, who, though overseas during this entire period, have kept up a constant correspondence with the rest of us, and thus shared with their cis-Atlantic colleagues the fruits of their many years of consideration of the vexing problem we had chosen to attack. Professor Strong’s book, The Origin of Consciousness, which contains a powerful argument for the epistemological view here also defended, came out after our essays were in practically their present shape. But several, at least, of us owe a peculiar debt, in the way of sharpening and filling out our analysis of the knowledge-situation, to the correspondence with him which preceded the publication of that book. Professor Strong, in turn, acknowledges indebtedness to Professor Santayana for the principal concept he employs in his analysis, that of “essence.” It seems desirable to mention specifically these debts, since most of the work of collaboration has necessarily been carried on by the other five members of the group, who were able to meet in person and correct one another s idiosyncrasies in oral discussion.

The doctrine here defended, while definitely realistic, is distinctly different from the “new” realism of the American group, whose volume, published in 1912, was a signal example of the value of co-operative effort in crystallizing and advertising a point of view in philosophy. Our realism is not a physically monistic realism, or a merely logical realism, and escapes the many difficulties which have prevented the general acceptance of the “new” realism. It is also free, we believe, from the errors and ambiguities of the older realism of Locke and his successors. To find an adjective that should connote the essential features of our brand of realism seemed chimerical, and we have contented ourselves with the vague, but accurate, phrase critical realism. Needless to say, the word “critical,” has no reference to the Kantian philosophy, which should not be allowed to monopolize that excellent adjective. Our choice of this phrase was confirmed by the fact that several members of the group had already used it for their views which, however divergent their expression, have been, we recognize, essentially the same.

This divergence in expression we have been content, in considerable measure, to retain. It reveals some slight divergences in emphasis, and in at least one point (noted in the opening essay in the footnotes on pp. 4 and 20, and discussed from one side in that essay and, at greater length, in the concluding essay) a difference in analysis, which is important, but does not imply a difference of opinion among us as to what the existential situation in cases of knowledge is. The decision to permit these variations in angle of approach and method of analysis to stand was due not merely to individual obstinacy of preference, but to a hope that they might serve to correct the misinterpretations of our position to which the confinement to one set of terms would inevitably lead. Probably no one of us would wish to express himself exactly as any of the others has done. But our familiarity with one another s meanings has enabled us to understand methods of expression from which at first we were inclined to dissent; and no essay has been included in the volume until it has been so revised as to meet with acceptance, on all the major points, from the other essayists.

It should be added, however, that no agreement has been sought except on the epistemological problem with which this volume is concerned; and, actually, the members of our group hold somewhat different ontological views. Critics of the volume are asked to bear this in mind, and not to confuse the discussion of the epistemological solution here offered by the introduction of dissenting opinions upon irrelevant topics.

We have found it entirely possible to isolate the problem of knowledge; and we believe that its solution lies along the lines that we have here indicated.


  • THE APPROACH TO CRITICAL REALISM. By DURANT DRAKE, Professor of Philosophy in Vassar College
  • PRAGMATISM VERSUS THE PRAGMATIST. By ARTHUR 0. LOVEJOY, Professor of Philosophy in Johns Hopkins University
  • THE PROBLEM OF ERROR. By ARTHUR K. ROGERS, Professor of Philosophy in Yale University
  • THREE PROOFS OF REALISM. By GEORGE SANTAYANA, late Professor of Philosophy in Harvard University
  • KNOWLEDGE AND ITS CATEGORIES. By ROY WOOD SELLARS, Associate Professor of Philosophy in the University of Michigan
  • ON THE NATURE OF THE DATUM. By C. A. STRONG, late Professor of Psychology in Columbia University

content forthcoming