“True philosophy is a living wisdom, for which there is no death.”

1790s, The Age of Reason, Part I (1794)

Letter to a Japanese Animal Welfare Society (1961)

Source: Rhetoric as Philosophy (1980), pp. 31-32
Context: In the second part of the Phaedrus Plato attempts to clarify the nature of “true” rhetoric. … it does not arise from a posterior unity which presupposes the duality of ratio and passio, but illuminates and influences the passions through its original, imaginative characters. Thus philosophy is not a posterior synthesis of pathos and logos but the original unity of the two under the power of the original archai. Plato sees true rhetoric as psychology which can fulfill its truly “moving” function only if it masters original images [eide]. Thus the true philosophy is rhetoric, and the true rhetoric is philosophy, a philosophy which does not need an “external” rhetoric to convince, and a rhetoric that does not need an “external” content of verity.

Plato, Phaedo

Original: (la) Quid est aliud de philosophia tractare, nisi verae religionis, qua summa et principalis omnium rerum causa, Deus, et humiliter colitur, et rationabiliter investigatur, regulas exponere? Conficitur inde, veram esse philosophiam veram religionem, conversimque veram religionem esse veram philosophiam.

De Divina Praedestinatione, ch. 1; translation from Kenelm Henry Digby Mores Catholici, vol. 8 (London: Booker & Dolman, 1837) p. 198.

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

as quoted in Londhe, S. (2008). A tribute to Hinduism: Thoughts and wisdom spanning continents and time about India and her culture https://books.google.com/books/about/A_Tribute_to_Hinduism.html?id=G3AMAQAAMAAJ

"Conflict in Vietnam and at Home" speech http://www.pbs.org/wgbh/amex/rfk/filmmore/ps_ksu.html at Kansas State University on March 18, 1968 as part of the Alfred M. Landon Lectures on Public Issues.