“Power of auto-suggestion known in the Middle Ages. The power of thought, of idea, is incommensurable, is immeasurable. The world is dominated by thought. The human being individually is also entirely governed by his own thoughts, good or bad. The powerful action of the mind over the body, which explains the effects of suggestion, was well known to the great thinkers of the Middle Ages, whose vigorous intelligence embraced the sum of human knowledge.”

Source: The Lost Symbol

Aphorism 3
Novum Organum (1620), Book I

"Einstein's Reply to Criticisms" (1949), The World As I See It (1949)
Context: The cult of individual personalities is always, in my view, unjustified. To be sure, nature distributes her gifts variously among her children. But there are plenty of the well-endowed ones too, thank God, and I am firmly convinced that most of them live quiet, unregarded lives. It strikes me as unfair, and even in bad taste, to select a few of them for boundless admiration, attributing superhuman powers of mind and character to them. This has been my fate, and the contrast between the popular estimate of my powers and achievements and the reality is simply grotesque. The consciousness of this extraordinary state of affairs would be unbearable but for one great consoling thought: it is a welcome symptom in an age which is commonly denounced as materialistic, that it makes heroes of men whose ambitions lie wholly in the intellectual and moral sphere. This proves that knowledge and justice are ranked above wealth and power by a large section of the human race. My experience teaches me that this idealistic outlook is particularly prevalent in America, which is usually decried as a particularly materialistic country.

Source: The Secret

As quoted in The Linguistic Relativity Principle and Humboldtian Ethnolinguistics : A History And Appraisal (1963) by Robert Lee Miller, and The Linguistic Turn in Hermeneutic Philosophy (2002) by Cristina Lafont
Context: The interdependence of word and idea shows clearly that languages are not actually means of representing a truth already known, but rather of discovering the previously unknown. Their diversity is not one of sounds and signs, but a diversity of world perspectives [Weltansichten]. … The sum of the knowable, as the field to be tilled by the human mind, lies among all languages, independent of them, in the middle. Man cannot approach this purely objective realm other than through his cognitive and sensory powers, that is, in a subjective manner.

As quoted in Self-Motivation Through Risk Taking! : Are You Leading Or Do You Wither with Problems? (2005) by M. Nadarajan Munisamy

Formal Logic (1847)

“Aren’t they all?” Sam asked him.
Source: Synners (1991), Chapter 5 (pp. 52-53)

Budget Debate, House of Commons, Ottawa, Ontario, March 22, 1943.