This amounts to saying that the discussion of philosophical problems takes especially a verbal aspect; and the more complex the phenomena a concept thus handled, contains, the more dangerous it is.

A concept of the colour red has but a very simple content, and by using it, this content can be very clearly represented.

But how can the immense meaning of the word "mind" be realised every time that it is used?
For example, to define mind and to separate it from the rest of the knowable which is called matter, the general mode of reasoning is as follows: all the knowable which is apparent to our senses is essentially reduced to motion; "mind," that something which lives, feels, and judges, is reduced to "thought." To understand the difference between matter and mind, it is necessary to ask one's self whether there exists any analogy in nature between motion and thought.

Now this analogy does not exist, and what we comprehend, on the contrary, is their absolute opposition.

Thought is not a movement, and has nothing in common with a movement.