Proposed psychometer index designed as an aid to the better determination of common fungoid illusions and of the comparative value of mental concepts.

The point around which the present argument hinges is the word illusion. By illusion is meant any error of sense, perception, memory, or representation, or of judgment based upon these which counterfeits reality.
The only way to distinguish any form of illusion would be to dispel the conditions unfavorable to the manifestations of healthy concepts.
It ought to be strongly impressed that there is no well marked line between the sane and the insane, and scarcely any where illusion is concerned, apart from its permanency.