798 



SCIENCE. 



[N. S. Vol. XX. No. 519. 



likelihood that one can breathe the eon- 

 fining air of the laboratory, or that one will 

 presently limit one's range of interests to 

 oneself. Partly it is a matter of tempera- 

 ment, partly a matter of chance introduc- 

 tion or of continued occupation. The two 

 types of psychologist are distinct: all the 

 more reason that they should work in har- 

 monious cooperation. 



I hope that, in this latter portion of my 

 address, I have not traveled too far out of 

 the record. Some men have problems 

 thrust upon them. And, after all, if what 

 I have said contributes ever so little to 

 the furtherance of mutual aid and the in- 

 crease of mutual esteem, as between psy- 

 chologists of different camps, I may hope 

 for forgiveness, even though I have exceed- 

 ed the letter of my instructions. Noav let 

 me briefly summarize what I have said. 

 I began, you will remember, by pointing 

 out that, above and apart from the many 

 special problems of experimental psychol- 

 ogy, there lies the great problem of self- 

 definition, of the range and scope of the 

 experimental method in psychology. Then, 

 under the headings of psychology proper 

 and of psychophysics, I called your atten- 

 tion to a series of laboratory problems that, 

 more or less insistently, more or less imme- 

 diately, call for solution. Whatever else 

 experimental psychology may be, I said, 

 these issues are issues of experimentaL psy- 

 chology. Incidentally, I deprecated any 

 departure, at the bidding of philosophy, 

 from the straight path of psychological in- 

 vestigation ; and I deprecated also that neg- 

 lect of introspective control in psychology 

 which has been the besetting sin of many 

 whose, direct interest lies in psychophys- 

 ics. I then went on to include in experi- 

 mental psychology the more objective ap- 

 plications of the experimental method in 

 child psychology, in animal psychology, in 

 abnormal psychology. It was not my 



province to detail the special questions in 

 these fields; they form the topic of other 

 addresses in other sections. But I should 

 regard as incomplete any review of the 

 problems of experimental psychology which 

 omitted reference to them. Their consid- 

 eration helps us to attack that first prob- 

 lem of definition, clarifies our method, and 

 furnishes an opportunity for the give-and- 

 take of criticism and encouragement. We 

 can not afliord to misunderstand one an- 

 other, as we can not ailord to waste our 

 time on unreal and constructive problems. 

 The work presses ; the rule of work is defi- 

 nite and unmistakable; there is room in 

 the workshop for all sorts and conditions 

 of men. I do not think that the outlook 

 of any science could be more hopeful; I 

 do not think that we need fear a lessening 

 of that quiet enthusiasm which, from the 

 first, in the beginner as in the mature stu- 

 dent, has been the salient characteristic of 

 the experimental psychologist. 



E. B. TiTCHENER. 



SCIENTIFIC BOOKS. 



An Introduction to the Theory of Mental 



and Social Measurements. By Edward L. 



THORNDHiE. New York, The Science Press. 



1904. Pp. 212. 8vo. Price, $1.50. 



In this book Dr. Tliorndike has undertaken 

 to explain the ' meaning and use ' of recent 

 contributions to statistical theory ' in com- 

 mon language to a common-sense thinker.' 

 " Knowledge will be presupposed of only the 

 elements of aritlimetic and algebra. Artifi- 

 cial symbols will be used only where they are 

 really convenient." In order are discussed: 

 Units of measurement, the measurement of 

 an individual and a group, the causes of 

 variability and the theory of probability, the 

 arithmetic of calculating central tendencies 

 and variabilities, the transmutation of meas- 

 ures by relative position into terms of units 

 of amount, the measurement of differences, 

 changes and relationships and the use of 

 tables, reliability of measures and errors of 

 measurements. 



