phenomenon that precede it. This leads us naturally to enquire whether, in the light of true philosophy, this study can constitute a separate and distinct science. But before that, we think it useful to translate the description of Psycho Physiology as given by its founder and most illustrious exponent, William Wundt. As late back as 1858, Fechner had already studied parts of this science, especially psycho physics, and published the results in 1860 in his Elements of Psycho Physics. In fact, on this special branch he is the most prolific and original writer. But Wundt was the first to plan and develop physiological psychology as a special science; and that is why we think it useful to show his exposition of the object, methods and results of the science he founded; needless to say, little has been changed by his successors as regards the general outlines. Parts have been completed, opinions differ on many points, but the creation of his mind remains substantially the same as he conceived it. 'This science,' says Wundt, 'is a combination of two sciences which for centuries have been studied separately.' Physiology sheds its light on the biological phenomena that our external senses perceive In psychology man sees himself, as it were, from inside, and his object in so-doing is to explain the linking together of facts which this internal observation furnishes him. Though our internal and external life present different aspects, yet they have many points of contact. Our internal experience is continually influenced by exterior causes on the one hand, and on the other these internal states of ours often exercise a decisive action on the evolution of the external fact. Thus is formed a circle of biological phenomena, simultaneously accessible to our observation, both internal and external; and, as long as psychology and physiology are kept separate, their bordering domains will be very appropriately assigned to a special science, intermediate between them. This science is physiological psychology.

A science, the object of which is the various points of contact of our internal and external life, is obliged to compare, as much as is possible, its own facts, notions, and results, with the body of data furnished by the two complementary sciences,

• The reason of this will appear later on, p. 18, sqq.

psychology and physiology. And the final object of its research is this: What is the mutual connection between our internal and external existence, in their ultimate and fundamental principle, the soul?

All converges towards this question and answer, in psychophysiology; both complementary sciences can put it off, as being outside their domain, but our science cannot do so. Our new science has, therefore, a double work to perform.

Firstly, to examine those biological phenomena which, holding a middle place between internal and external experience, necessitate a simultaneous application of the two methods of internal and external observation.

Secondly, once this domain is investigated, it must utilise the views thus obtained, to enlighten the body of biological phenomena at our disposal, so that it may the better unveil and help us to understand human being in its entirety.

To determine the order to be followed in this double pursuit, we must remember that going over the roads connecting internal and external activity, our science follows, in the first instance, those ways which conduct from the outside world to our interior life; in other words, it begins by studying physiological phenomena, and tries to show their influence and bearing on the domain of internal observation. Then only does its examination extend to the reactions which our internal being exercises on that part of us in direct communication with the outside world. Thus it is that it regards chiefly the psychological side of things, and this conception we express by the very name of the science, physiological psychology. The adjective determines, specifies the point of view of the object proper.

Wundt now considers the origin of this new science.

The reason of the relation which we establish between the two sciences, is, that all those problems that have reference to the corelations of our internal and external life have, until now, been a constitutional part of psychology; whilst physiology had resolutely excluded from its domain all questions that claimed any particular intervention of speculation.

We commend this assertion of Wundt by saying that though to a certain extent, owing to the great increase of

knowledge in sciences, a separation of all 'speculation' was inevitable, neverthelesss, this separation was greatly facilitated by the ridicule that was heaped on the decident scholastic philosophy, not only by the forerunners of modern science, but also by the literary renaissance of the sixteenth century, and subsequently. As regards the first part of this assertion, we easily understand that, owing to the rudimentary state of science, comparatively little was known as regards the 'co-relations of our internal and external life; but that their importance was understood is evident from a study of the De Anima of Aristotle, and its commentary by St. Thomas Aquinas. Moreover, it will subsequently be shown that according to the views of those who dominated the world of philosophy ever since the decadence of scholasticism in the fifteenth and sixteenth centuries, such a science as physiological psychology professes to be was, a priori, impossible. Alone, the psychology of Aristotle and of St. Thomas was broad enough, corresponded well enough to facts, to show that such sciences were possible.

Nevertheless [continues Wundt], modern philosophers, and especially psychologists of the second quarter of last century, began by rendering themselves more familiar with physiological experiments; simultaneously, physiologists felt the necessity of consulting psychology, in certain questions that bordered on their proper domain, and imposed themselves on the attention of scientists. Resulting from such needs, the bringing together of these two sciences gave birth to physiological psychology. And the instruments used by this new science to unravel these new problems, are also borrowed from the two parent sciences; psychological, internal observation of our own conscious self, is helped, step by step, by the use of methods belonging to experimental physiology; so much so, that the physical methods of this latter science, as applied to our conscious states, has given rise to a special branch of experimental investigation, to psycho-physics. The methods of measurement used in this special science show well how both the special and general sciences in question depend on the state of knowledge in other departments. The instruments used, such as the Dynamometre and others, mostly furnish their indications by electric apparatus of a complicated nature, so that we may well say that the sciences of psycho physiology and psycho-physics were, even at the beginning of last century, as unreliable as was astronomy before the invention of telescopes and other modern methods of investigation.

Two important phenomena clearly mark the limits where external observation ceases to be sufficient, and where internal observation becomes necessary; and vice versa.

These phenomena are: sensation, which is at the same time a psychological fact, but which directly depends on certain fundamental external conditions; and, secondly, the movement of internal impulsion, a physiological phenomenon, the causes of which are, generally, only revealed by internal observation of self.

In sensation, we see the border of the two domains, as it were, from inside, the psychological view; in movement, we see the same border from the outside, the physiological view.7

We must, then, begin our study by determining how sensations correspond, in quality and in intensity, to their external causes, the physiological excitants of our senses. This necessitates a study of the structure and functions of the nervous system of man, so that we may see how it acts in response to the different forms of stimuli which excite it. Sensations in given conditions engender representations, a certain knowledge the direct object of which is our own conscious state, the indirect object being the external things that caused this conscious state in the first instance. These representations are composed of elements, which are called, in psycho-physiology, impressions. And these are studied in a second section, the physiological bases of the science forming the first section.

An 'impression,' then, is one of the simple elements that go to make the complex, distinct and conscious act, a 'representation' (which corresponds, more or less, to what we call a 'perception'). These impressions do not exist singly, being merely the result of a mental abstraction that analyses the concrete whole, the 'representation,' into its elements. They are not conscious, and are indistinct. They are caused by one of the elements or qualities of the concrete object that 'presents' itself to us.

These impressions, before yielding to our consciousness a representation, are arranged in a double chronological and

7 Wundt, Elements of Physiological Psychology, 2nd edition, vol. i. Introduction.

8 This character is clearly understood in the usual signification of this word, as when we say: I am under the impression,' we often mean that we have a vague idea.'

spacial order. In other words, we study according to what laws these impressions are united in our sensitive faculty, in order to form the conscious phenomena which we call a 'representation.' For instance, an auditive image or representa tion has a special connection with the chronological order and its impressions, whereas a visual precept is chiefly concerned with the spacial arrangement of its constituting impressions. Wundt calls this latter ordination an 'extensive order.' These two orders are always present in all our representations. But in some, one order is more characteristic because more pronounced, than in other perceptions.

Tactile representations contain both both orders equally developed. After this, we consider the relations of these representations with our consciousness, their psychic aspect, and thus we study sentiments, not merely as being agreeable or not, but under their esthetic aspect. We thus exceed purely sensorial sentiments, that are considered merely in their connection with the sensations that cause them.

Finally, in a last section, comes the study of complex representations, that is to say, the 'laws of association' of representations, and the method we employ is the analysis of consciousness, and the study of the 'course' or progress of our conscious perceptions.

In commenting on Wundt earlier in this essay, we were led to consider the relations of this science with philosophy, and in particular with that of Aristotle and St. Thomas Aquinas. As this is of special interest to Catholic philosophers of the present day, a development of this consideration

may be useful. Several neo-scholastic philosophers look askance at this new science, partly through prejuuice against any new science-the same state of mind that ruined scholasticism in the sixteenth century-and partly through not understanding fully the object and end pursued by this new movement, have steadily neglected it in their studies and in their teaching. Now, undoubtedly, the most important of Catholic schools of philosophy of the present day is the school whose method is the application of the old synthesis of Thomism to modern science, in all its branches. And the school that has acquired by far the most influence and

VOL. XIV.

B