2 NATURE 
[| NOVEMBER I, 1906 
The last chapter contains a warm defence of the 
utility of symbolic logic, though the author does not 
claim that it can be used directly by natural science. 
(3) Mr. Joseph’s worl is on very different lines 
from the two foregoing. It is an excellent and very 
sound exposition of the traditional logic for which 
Oxford has been famous ever since the days of 
Chaucer’s Clerk. But if the matter is traditional, the 
manner of exposition is as fresh and independent as 
it could well be, and the author has entirely fulfilled 
the desire expressed in his preface not to teach any- 
thing to beginners which they should afterwards have 
merely to unlearn. Especially valuable are some of 
the discussions of particular topics, e.g. of the prin- 
gipium individuationis (on p. 76), or (on p. 275) of 
the passage from Aristotle’s ‘‘ Categories’? which is 
sometimes quoted as a source of the ‘‘ Dictum De 
Omni.’’ We note, too, Mr. Joseph’s irresistible objec- 
tions to classificatory division by dichotomy, so 
zealously defended by Jevons and the others who won 
our earliest logical sympathies, and his rejection (in 
excellent company) of the doctrine of the inverse re- 
ation of extension and intension. 
Mr. Joseph has interesting remarks to make on the 
relation between mathematics and logic, and a good 
statement of the doctrine that the principle of syllo- 
gistic inference cannot be made into the premiss of a 
- particular syllogism without begging the question. 
His chapter entitled ‘‘ The Presuppositions of Induc- 
tive Reasoning: the Law of Causation,’’ is a model 
of clear and forcible reasoning. Mill’s four methods, 
he finds, may be reduced to one ‘“‘ method of experi- 
mental inquiry,’’ which is ultimately based on dis- 
junctive reasoning, and the essence of which is ‘‘ that 
you establish a particular hypothesis about the cause 
of a phenomenon, by showing that, consistently with 
the nature of the relation of cause and effect, the 
facts do not permit you to regard it as the effect of 
anything else.”’ 
There is a valuable seven-page discussion (pp. 
352-8) of the inductive syllogism in Aristotle, whom 
the author seeks to defend—not without qualifications 
—from the objection that, after all, his induction 
rests on complete enumeration, and that thus deduc- 
tion from any premiss so gained becomes a hollow 
pretence. Where the units are species, he points out, 
and one wants to prove something about the genus 
to which they belong, complete enumeration is 
possible and legitimate: but where the units are in- 
dividuals, one does not (according to Aristotle) work 
by an inductive syllogism that summons all the 
instances; one learns the essential nature of the 
species to which they belong by induction, but the 
induction is now a psychological rather than a logical 
process, and we arrive at the conclusion, not through 
an inductive syllogism, but ‘‘ in virtue of the necessary 
relation between the two terms which our familiarity 
with particulars makes possible, but which is the 
work of intellect or nous.’? We should have wel- 
comed in this connection a detailed exposition of 
some of the difficulties in the concluding chapter of 
the Posterior Analytics. 
(4) This volume is the first instalment of what 
NO. 1931, VOL. 75] 
promises to be an important inquiry, ‘ inductive, 
psychological, genetic,’’ into the actual movement of 
the function of knowledge. The author distinguishes 
genetic logic from formal (or the logician’s) logic, 
and metaphysical logic (or logicism), and he describes 
genetic logic as the physiology and comparative 
morphology of knowledge—physiology because it 
examines function, and comparative morphology be- 
cause ‘‘it asks about the relation of the forms and 
other logical determinations of the several modes of 
cognitive process to one another, and aims to make 
out an interpretation of the series of forms as con- 
ditioned upon functions.”’ 
Prof. Baldwin’s account of the process by which 
cognition is built up is so coherent and intricate that 
it is impossible to give more than a fraction of its 
substance here. He begins with the condition of bare 
awareness of an object, the a-dualistic consciousness, 
examines the place of interest as a factor in the deter- 
mination of the object, and the meaning of various 
terms like disposition, autonomic, heteronomic, 
control, project, reality coefficient; shows how “‘ it is 
the stimulation, not the response, that is the con- 
trolling factor in the construction of sense objects,”’ 
and how the first distinction is made in the perception 
of persons and things. Then he passes to image 
objects and memory objects, and discusses the pro- 
cess by which the inner-outer dualism is reached. 
This leads him to an examination of play or make- 
believe objects, and then we have three valuable 
chapters on various aspects of meaning. Lhe last 
two chapters deal with the mind-body dualism and 
the dualism of subject and object. 
The terminology of the work is not of tke sim)!.» 
but behind it one finds that the writer has something 
true and important to say. Two other volumes—one 
on experimental logic and one on real logic—will 
complete the work, which is being published simul- 
taneously in English and French. 
1 
A MANUAL OF PHARMACOLOGY. 
By Dr. W. E. Dixon. 
and 
A Manual of Pharmacology. 
Pp. xii+451; mumerous curves, diagrams, 
formule in the text. (London: Edward Arnold, 
1906.) Price 15s. net. 
HARMACOLOGICAL literature in the English 
language has during the last few years in- 
creased considerably, and this is true even if we 
exclude the copious additions to this literature eman- 
ating from America. Students of pharmacology at the 
present time have at least three exhaustive text-books 
to choose from, all up to date, and written by teachers 
actively engaged both in teaching and original re- 
search. In each of these works the classification of 
the subject adopted is markedly different, from which, 
perhaps, the philosophical reader would be apt to infer 
that in the present state of our knowledge, whether of 
the action of drugs or of the chemical composition of 
their active ingredients, no absolute classification is 
possible. In the book before us prominence is certainly 
given in determining classification to the physiological 
action of the drugs in question, and in the present 
