John Wesley Powell,
Truth and Error — Chapter XXIV.
(1898)
“ Plato taught that form is the substrate of all properties. This he did with such literary skill that he held the judgment of mankind for many centuries. He not only taught that form is the substrate of physical properties, but also of thought. To him thoughts were forms given off by objects floating in the empyrean and taken into the mind, and his exposition of this doctrine transferred the word idea from the realm of space to the realm of mind. A monument to this fallacy still exists in the use of the term idea for a notion in every modern language of civilization. ”
