“Poincaré's mind was not subject to hysteresis or hibernation. He had the unique faculty of dismissing an idea from his mind, the instant the stimulus was gone, and to supplant it immediately with another creative idea.”

1970s and later

"Whether Genius is Conscious of its Powers?"
The Plain Speaker (1826)

The Law of Mind (1892)

Source: Wings of Fire, p. 32.

As quoted in Russia and the Independent States (1993) by Daniel C. Diller, p. 446
1990s
Context: Liberty sets the mind free, fosters independence and unorthodox thinking and ideas. But it does not offer instant prosperity or happiness and wealth to everyone. This is something that politicians in particular must keep in mind.

"Man's Glassy Essence" in The Monist, Vol. III, No. 1 (October 1892)
Context: The consciousness of a general idea has a certain "unity of the ego" in it, which is identical when it passes from one mind to another. It is, therefore, quite analogous to a person, and indeed, a person is only a particular kind of general idea.

Original: Le persone creative amano la solitudine. È fondamentale, durante una riflessione o un momento creativo, avere intorno a sé un silenzio totale, per confidare al proprio corpo le idee della mente.
Source: prevale.net

The Law of Mind (1892)
Context: We are accustomed to speak of ideas as reproduced, as passed from mind to mind, as similar or dissimilar to one another, and, in short, as if they were substantial things; nor can any reasonable objection be raised to such expressions. But taking the word "idea" in the sense of an event in an individual consciousness, it is clear that an idea once past is gone forever, and any supposed recurrence of it is another idea. These two ideas are not present in the same state of consciousness, and therefore cannot possibly be compared.