NATURALISM, a term which, in the his tory of philosophical thought, has received a variety of meanings. In general it. refers to that which is in accordance with nature. But the sense in which the term nature may be used is not by any means a constant but a variable, and as this sense varies we will find a set of corresponding meanings for naturalism itself. Nature may be considered as that which is the opposite of the artificial, the conventional or the traditional. Regarding nature from this point of view, the term naturalism will be em ployed in much the same sense as that in which Rousseau used it in his plea for a return to nature in matters philosophical, religious and political. Or nature may be regarded as the external reality which furnishes the material of all our sensations; naturalism will then signify in the Lockeian sense that which is original and fundamental in knowledge as opposed to that which is the result of the operations of the human understanding. Again, nature may sig nify the basis of natural affections and dis positions as opposed to the fundamental prin ciples of conduct which are revealed in the "dry light of reason.* In this sense Shaftes bury uses nature and naturalism in contrast to the rationalistic ethic of his day. Naturalism also has been used as a term to characterize such a philosophical system as that of Giordano Bruno, which identifies God with nature, and does not distinguish between the Creator and his works. In the midst of this confusion of meanings, however, the present day discussions in philosophy have established a determinate usage which for the most part is uniformly recognized, and consistently employed. This usage is quite different from any of the phases which have been mentioned, and may be de fined somewhat as follows: Naturalism signi fies a method of interpreting the subiect matter of philosophy, which insists that all phenomena whatsoever are to be explained according to the laws of nature, that efficient causes only are to be regarded, while all considerations of final causes are to be rigorously excluded, as well as those alleged ideal implications of reason which postulate some metaphysical necessity as a mode of interpreting physical phenomena.
In this sense naturalism, as regards psychol ogy, grounds all psychical phenomena upon a purely sensationalistic basis; there is no self in the sense of an organizing power and unitary centre in the midst of the various states of consciousness; the spiritual elements of con sciousness are regarded as incidentaL and deter mined at the last analysis by the cosmic proc esses. As a theory of knowledge, there is no place for an idealistic construction of the data of experience. In ethics, naturalism is a sci
ence of what is and not of what ought to be. It allows a science of ethics but not of meta physics. It cosmology essays an explanation of the universe in terms of the laws of nature which inductive research may have discovered, but it has no concern or interest as to the ques tion whether "through the ages one increasing purpose runs." A system of naturalism, however, is not necessarily a philosophy of materialism any more than it is necessarily pantheistic, although it must be acknowledged that naturalism and materialism are often used as synonymous terms. It is not used in the present day as a term opposed to supernaturalism, as it is essen tially a philosophical term and not used in a theological sense. It does not deny a super natural reality in the theological sense; it is merely not interested in the questions which turn upon a beyond and above as regards human thought and human activity.
The antithesis which the term naturalism suggests does not lie in this direction. To understand the significance of naturali: m, and it must be understood in order to appreciate in any adequate measure the philosophical prob lems of the day, the exact antithesis which is implies must be clearly Ireheaded. The anti thesis is between an ex anation of the phe nomena of existence which can be expressed solely in terms of the laws of nature, and all explanations on the other hand which involve fundamental thought necessities as essential factors. The antithesis is between the natural and the rational, between the natural and the spiritual. This usage of the term we find in such a book as that of Balfour's 'Grounds of Belief,) or in Ward's 'Naturalism and Agnos ticism,) or in Sorley's 'Ethics of When Mr. Balfour's book was first published he was severely criticised in some quarters for his use of the term naturalism. This evoked much discussion, which has served to establish a definite and determinate sense in which the term may be used. A most able and satisfac tory defense of Mr. Balfour's usage of the term is to be found in the work of Prof. Andrew Seth, entitled 'Man's Place in the One of the essays is 'The Use of the Term Naturalism,' and it is one of the best discussions to which any student of the subject can be referred. Without doubt, the element of variability which has attended the history of this term has been to a large extent, if not al together, removed, and a constant significance has resulted which conforms to the general usage of the present time; and the significance is the one which it has been the endeavor of this article to present.