“Not only must philosophy be in agreement with our empirical knowledge of Nature, but the origin and formation of the Philosophy of Nature presupposes and is conditioned by empirical physics. However, the course of a science's origin and the preliminaries of its construction are one thing, while the science itself is another. In the latter, the former can no longer appear as the foundation of the science; here, the foundation must be the necessity of the Concept.”

But philosophy has always been, and will always be, a fight with and a conquest of self-evident truths; philosophy is not looking for any "natural necessity", it sees in naturalness and in necessity alike an evil magic, which, if one cannot quite shake it off (for in this no mortal has ever yet succeeded), yet one must at least call by its right name; and even this is an important step! p. 342
Source: In Job's Balances: on the sources of the eternal truths, Words That Are Swallowed Up - Plotinus's Ecstasies

Source: The Life of the Mind (1971/1978), p. 7.

Source: Signs, Language and Behavior, 1946, p. 238; as cited in: Adam Schaff (1962). Introduction to semantics, p. 88-89

Source: 1940s and later, Otto Neurath Economic Writings. Selections 1904-1945 (2004), p. 269

Source: Talking Science: Language, Learning, and Values. 1990, p. 175; as cited in: Hanuscin, Deborah L., and Michele H. Lee. "Teaching Against the Mystique of Science: Literature Based Approaches in Elementary Teacher Education." Learning, Teaching, and Curriculum presentations (MU) (2010).

Annotations to Sir Joshua Reynolds's Discourses
1790s

Source: A Treatise on the Seven Rays: Volume 4: Esoteric Healing (1953), Vaccines, p. 322/4

Source: Course of Experimental Philosophy, 1745, p. v: Preface
Context: All the knowledge we have of nature depends upon facts; for without observations and experiments our natural philosophy would only be a science of terms and an unintelligible jargon. But then we must call in Geometry and Arithmetics, to our Assistance, unless we are willing to content ourselves with natural History and conjectural Philosophy. For, as many causes concur in the production of compound effects, we are liable to mistake the predominant cause, unless we can measure the quantity and the effect produced, compare them with, and distinguish them from, each other, to find out the adequate cause of each single effect, and what must be the result of their joint action.

Subjectively speaking, the essence of philosophy is certitude; for the moderns, on the contrary, the essence of philosophy is doubt: the philosopher is supposed to reason without any premise (voraussetzungsloses Denken), as if this condition were not itself a preconceived idea; this is the classical contradiction of all relativism. Everything is doubted except for doubt. The solution to the problem of knowledge − if there is a problem − could not possibly be this intellectual suicide that is the promotion of doubt; on the contrary, it lies in having recourse to a source of certitude that transcends the mental mechanism, and this source − the only one there is − is the pure Intellect, or Intelligence as such.
[2005, The Transfiguration of Man, World Wisdom, 3, 978-0-94153219-8]
Miscellaneous, Philosophy