141 
if they existed in different planets of our solar system, or in 
planets, or sans of different systems.* 
The brain is always changing. “ The cerebral cortex, ”f 
says the paper, “ is constantly receiving new accretions, and 
undergoing novel combinations. - ” As well as every other por- 
tion of our visible body, our brain u is transitory, J undergoing 
ceaseless flux.” And, even if science succeed in detecting all 
the movements of the brain, it would only be the external 
mechanical movements that would be discovered. 
Mind 
is a spiritual substance, and belongs to psychology ; and “ an- 
enumeration of its various states constitutes our definition of 
mind.”§ 
“ Mind is that which reasons, imagines, wills, loves, fears, 
perceives, remembers, compares, is susceptible of all the 
various emotions, and is the only subject of feeling and affec- 
tion.” || 
Mind is One. 
“ The mind is one, and indivisible -If Our feelings are states 
of something which is one and single, not a plurality of sub- 
stances ; for the principle of thought is not divisible into 
parts.” That the Ego is one, we need no other witness than 
our own consciousness; and <f the unity of consciousness is 
a fact known to us by much better evidence than the existence 
of matter.”** 
“ The sentient mind is essentially one, not extended and 
divisible, but incapable by its very nature of subdivision into 
integral parts, and known to us only as the subject of our 
consciousness in all the variety of successive feelings which we 
comprehend under that single name.”tt 
But though not capable of division, it is capable of exten- 
sive analysis, as it exists in different states ; yet every thought 
and feeling is as single and indivisible as the mind itself, 
being the mind existing at a certain moment in a certain state. 
Mind a Substance. 
We have said that mind is a spiritual substance. But 
may it not be an imaginary, rather than a spiritual, substance ? 
* Brown , vol. iv., p. 410. t Page 124. 
t Contemporary Review , vol. xxv., p. 128. § Brown , vol. i., p. 292. 
|| Ibid., p. 157 ; vol. iii., p. 66. IF Ibid., vol. iv., p. 421. 
** Cook’s Lectures, p. 60. ft Brown, vol. iv., p. 424. 
