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order, and important questions of logical definition, which we have not suffi- 
cient time to discuss in their entirety. One thing is obvious on the most 
cursory perusal of many modern works ; that our physical philosophers — men 
who are great in their own sphere of thought — are in the habit of trespassing 
on domains of metaphysics, mental philosophy, and logic, which they have 
never studied ; and thus they invest their utterances on these subjects with 
the halo of their well-earned reputation as Physicists. But a high reputation 
in one line of thought is no guarantee for ordinary correctness in another. 
Mr. Darwin’s high reputation as a naturalist has certainly not prevented him 
from exhibiting himself weaker than other men when he has attempted to 
deal with questions which properly belong to Moral Science. But with 
respect to the paper and the discussion on it : it is evident that we greatly 
need a definition of some kind, which will enable us to attach a consistent 
meaning to the term “ Force ; ” and that our want of it involves us in hope- 
less confusion. At present we designate two things, while differing in their 
conception, by the same term — “ physical force ” and “ mental force.” As 
long as we do this, how is it possible to avoid confusion of thought ? The 
one is an idea derived froni certain phenomena in external nature ; the 
other from our consciousness of our own voluntary agency. When two 
trains run into one another, we have an example of physical force. When 
a great orator persuades a Parliament to do the very contrary to that 
which they intended to effect, we have an example of mental power. But 
the two acts differ from each other by the entire interval which separates 
matter from mind. Yet it is not uncommon to hear “mental forces” 
and “ material forces ” spoken of as if they were the same thing — nay, it is 
even asserted that they can correlate into each other. This confusion of 
thought has enveloped much of the reasoning on this subject in a complete 
fog ; so that we are in danger of missing our road in places with which we 
are entirely familiar. The use of this and of several other kindred terms is 
at present in a state of hopeless confusion. It is really high time that 
some system of definition should be adopted which will enable us to 
know what we are talking about. At present even eminent physical 
philosophers use the term force in different senses, and when they apply the 
same term to denote certain powers of the mind, our confusion becomes 
inextricable, acrimonious discussions ensue, and after all it turns out that 
instead of striking at each other, we have been striking at things wholly 
different, and that the whole has resulted in nothing but a wasteful expen- 
diture of valuable power. How is it possible that any reasoning can end in a 
useful result, when one man is talking about one thing, and another about 
a thing quite different. This loose use of language involves us in endless 
contradictions. Take for an example the use which is made of the word 
motion. What does it mean ? Surely, if it has any meaning at all, it can only 
mean change of position in space. It is that obvious thing which we see every 
day before our eyes. But we hear people talk of latent motion , or stored-up 
motion , as though, when the motion of a body ceased, there was not an end of 
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