75 
appears as a knowable phase of what we call matter, and now 
as the knowing act of what we call mind, while of the nature 
of the two-faced force we can know nothing more than is 
given in these transient phenomena, while the permanent 
existence of the subject of either is simply the longer per- 
sistence of the force which manifests itself through either 
aspect of these bi-polar phenomena. To reach any scientific 
conviction would seem to require a mind to be convinced, but 
this philosophy knows no mind, but only a state that is cor- 
related to a phase of the nervous system which is but another 
phase of other agents sublimated to or through higher removes 
of refinement, from the preceding simpler elements, or the- 
simpler phenomena that went before. No explanation can be 
given of the plausibility of such a theory except that its 
theory of the soul is purely physiological. None of these 
most dexterous word substitutions or subtle interchanges of 
thought can be accepted as the equivalent for the emphatic 
assertion of its own being which the soul makes to itself in 
every step of its knowing, and which it emphasises more 
positively the higher it rises in scientific achievement. 
(3.) We pass next to the conditions of knowledge in the 
apprehension of which the physiological metaphysics claims 
special advantages. It has learned, on the one hand, to 
recognize the necessity of certain categories which must be 
assumed as unquestioned and primitive in order that science 
may be possible, but cannot recognize them as either forms 
of being or forms of mind, because, according to the physio- 
logical theory, beings and mind are varying states or pheno- 
mena of the unknown force themselves which are more or 
less persistent, evolving one another by differences that 
divide and combinations that unite. There are relations, 
however, ever recurring, which mix with all our knowing and 
enter into all our experiences, and which accompany all our 
beliefs, and are especially conspicuous in the high generaliza- 
tions of scientific thought. It is true that physiologically 
conceived, as has already been explained, relations are only 
feelings, more transient than the feelings between which they 
are said to exist — i.e ., are experienced in the mind's transition 
from one feeling to another. There are relations between 
complexes of feelings and also between complexes of relations. 
These relations, like all other mental experiences, involve 
certain definite activities of the nervous organism, which, if 
often repeated, tend to perpetuation. Let it now be supposed 
that certain relations, as of causation, or time and space, both 
in their specialized and more general forms, should often be 
g 2- 
