8 TRANSACTIONS OF THE PLYMOUTH INSTITUTION. 
material substance is given, and is therefore as distinguished from 
these relative qualities unknown and inconceivable. 
"The same is true as regards mind. In so far as mind is the 
common name for the states of knowing, feeling, willing, desiring, 
&c, of which we are conscious, it is only a name for a certain 
series of connected phenomena, and consequently expresses only 
what is known. But in so far as it denotes that subject or sub- 
stance in which these phenomena inhere, it expresses what in its 
absolute existence is unknown." 
But is not this overstating the case. That our senses often give 
us false impressions is true, and that their information is very 
partial and often insignificant, must be allowed. 
Take the illustration most commonly given, that of sound. 
If we hear the blow of a hammer on an anvil, it appears to us 
that the sound is produced there where the hammer touches the iron. 
If w T e hear it at a greater distance we hear the sound some time 
after we see the blow fall, and it appears then to us that the sound 
has traversed the space straight to us from the blow. But when 
we find that all persons standing at a distance in a circle around 
the anvil hear the sound after the blow is struck, but at the same 
time as one another, we get the idea that the sound has travelled 
from the centre like a circular ripple on a pond when a stone is 
thrown in ; and when we find that the same holds good in all 
direction of space, we get the idea that the sound has progressed 
like a rapidly-expanding bubble. Still we conceive it as sound 
proceeding in this form. But when we are shown that sound is 
only a sensation produced in the ear, not at all like what pro- 
duced it, we gain the further conception of this bubble being 
only a film of compressed air, or motion communicated to the 
particles of air without their being any sound at all outside 
our ear. The question arises, What has become of our absolute 
knowledge 1 We thought we were absolutely certain " we heard 
a sound." 
If anything exists and has relations, including actions and 
reactions, what do we mean by having absolute knowledge 
concerning itl Is it not absolute knowledge if we know that 
it does exist, and has such and such relations, actions, and 
reactions 1 What more can there be to know about it 1 
To say therefore that we do not know anything absolutely 
about the substance of matter or mind seems to me in reality 
