ABSTRACT
Early in the course of the composition of the Principles of Psychology in their original form—that is, in 1854—Herbert Spencer had reached that conception of evolution as a universal process which he subsequently worked out in detail in the essay on Progress: Its Laws and Cause. The aim of the Principles of Biology was, as Mr. Spencer himself stated in the preface, to set forth the general truths of biology as illustrative of and as interpreted by the laws of evolution.” The whole body of philosophy, or completely-unified knowledge, Mr. Spencer divides into two parts: “On the one hand, the things contemplated may be the universal truths: all particular truths referred to being used simply for proof or elucidation of these universal truths. On the other hand, setting out with the universal truths as granted, the things contemplated may be the particular truths as interpreted by them.
