----- 威廉詹姆斯和亨利柏格森
Of the six chapters of the book, two, in slightly different form, have been printed before, the first in the Philosophical Review, the fourth in Mind, and I acknowledge with thanks the editors' pernnss1ons to reprint these chapters. To my friends Dr. H. M. Sheffer, Mr. Alfred D. Sheffield, and Dr. H. G. Brown I owe a greater debt than I can repay for careful examination of the proofs and many valuable suggestions.
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