149 
Those notions of the relation of simpler notions which I 
have called “ thoughts” are obviously of different kinds. 
We may have a relation between class and class, or be- 
tween individual and class, or between individual and 
individual. And so by a simple calculation we may see 
that there are nine different processes of the mind: from 
the relation between classes to another between classes, or 
between individual and class, or between individual and indi- 
vidual; or, again, from the relation between individual and 
class to that between classes, or from that between individuals 
to that between classes, or between individual and class ; or 
from that between individual and class to another between 
individual and class, or between individuals, or from a relation 
between individuals to another between individuals. The first 
three of these processes coincide mainly (for I shall not weary 
you by analysing too closely) with what is termed Deduction, 
or Synthesis ; the next three with Induction, or Analysis ; the 
remaining three, though least scientific in appearance, are as 
a matter of fact the commonest processes of all. We habitually 
reason from individual cases to individual cases. It is the 
opinion of many logicians that in such reasoning we insensibly 
generalize and particularize again ; they conceive that a process 
from individual to individual is impossible, and that the mental 
road lies through a universal. With all due deference to high 
authority, I am inclined to maintain the opposite, and to hold 
that the mind does actually proceed from one individual notion 
to another, without passing through any induction, rapid or slow. 
Each of these mental processes has its own special law or 
rule of guidance. The law of Deduction is expressed — or was 
intended to be expressed — in the “ dictum de omni et nullo 33 
of old logicians. We may term it the law of “ Universal 
Truth.” Granted a general proposition, it is equally appli- 
cable to every case which comes under it. Granted a relation 
between classes, that relation holds good for every portion of 
those classes. 
The rule of Induction may be characterized as the law of 
Uniformity.” Observed a fact with regard to an individual, 
supposing that individual to be the adequate representative of a 
class , you can infer a class -relation. 
The law of the third process of the mind I shall term “ the 
law of Analogy.” Observed a fact with regard to an individual, 
you infer a similar fact about another similar individual. 
If these somewhat broad statements about the laws of the 
three mental processes be taken as in the main correct, we can 
easily see where error may arise ; namely, from some violation 
of the special law which regulates the truth of the process. 
