I Animal Life and Ours 349 



life, we call Physics and Chemistry, of which astronomy, geology, 

 etc., are special departments. 



(2) But we also know something about plants and animals, and 

 while all that we know about them is still dependent upon changes 

 of matter and motion, yet we recognise that the activities of the 

 organism cannot at present be expressed in terms of these. There- 

 fore we find it convenient to speak of life as a new reality, while 

 believing that it is the result of some combination of matters and 

 energies, the secret of which is hidden. 



(3) But we are also aware of another reality, our own mind. Of 

 this we have direct consciousness and greater certainty than about 

 anything else. And while some would say that what we are 

 conscious of when we think is a protoplasmic change in our brain 

 cells or is a subtle kind of motion, it is truer to say that we are 

 conscious of ourselves. It is our thought that we know, it is our 

 feeling that we feel, and as we cannot explain the thought or the 

 feeling in terms of protoplasm or of motion, we find it convenient to 

 speak of mind as a new reality, while believing it to be essentially 

 associated with some complex activity of protoplasm the secret of 

 which is hidden. For our knowledge of our own mental processes, 

 and of those inferred to be similar in our fellows, and of those 

 inferred to be not very different in intelligent animals, we establish 

 another science of Psychology. 



(4) But we also know something about the life of the human 

 society of which we form a part. We recognise that it has a unity 

 of its own, and that its activities are more than thgse of its 

 individual members added up. We find it convenient to regard 

 society as another synthesis or unity — though less definite than 

 either organism or mind — and to our knowledge of the life and 

 growth of society as a whole, we apply the term' sociology. 



Thus we recognise four orders of facts and four great sciences — 



4. Society .... . Sociology. 



3. Mind ... . . Psychology. 



2. Life Biology. 



I. Matter and Energy . . . Physics and Chemistry. 

 Each of these sciences is dependent upon its predecessor. The 

 student of organisms requires help from the student of chemistry 

 and physics ; mind cannot be discussed apart from body ; nor can 

 society be studied apart from the minds of its component members. 

 Each order of realities we may regard as a subtle synthesis of 

 those which we call simpler. Life is a secret synthesis of matter 

 and energy ; mind is a subtle form of life ; society is a unity of 

 minds. 



But it must be clearly recognised that the "matter and energy" 

 which we regard as the fundamental realities are only known to us 



