“Philosophy is not politics, and we do our best, within our all-too-human limitations, to seek the truth, not to score points against opponents. There is little satisfaction in gaining an easy triumph over a weak opponent while ignoring better arguments against your views.”

As he responded to an interview in the newspaper "Kathimerini" when asked whether he is a far right(10 September 2017)
Source: http://www.kathimerini.gr/925987/article/epikairothta/politikh/adwnis-gewrgiadhs-den-yphr3a-pote-moy-akrode3ios

"The Vietnam Negotiations", Foreign Affairs, Vol. 48, No. 2 (January 1969), p. 214; also quoted as "A conventional army loses if it does not win. The guerilla army wins if he does not lose."
1960s
Context: We fought a military war; our opponents fought a political one. We sought physical attrition; our opponents aimed for our psychological exhaustion. In the process we lost sight of one of the cardinal maxims of guerrilla war: the guerrilla wins if he does not lose. The conventional army loses if it does not win. The North Vietnamese used their armed forces the way a bull-fighter uses his cape — to keep us lunging in areas of marginal political importance.

Variant: Science advances one funeral at a time.

Plato, Phaedo

143
Fruits of Solitude (1682), Part I

"As I Please," Tribune (8 December 1944)^{http://alexpeak.com/twr/tdoaom/}
"As I Please" (1943–1947)
Context: The thing that strikes me more and more—and it strikes a lot of other people, too—is the extraordinary viciousness and dishonesty of political controversy in our time. I don't mean merely that controversies are acrimonious. They ought to be that when they are on serious subjects. I mean that almost nobody seems to feel that an opponent deserves a fair hearing or that the objective truth matters as long as you can score a neat debating point.

No Compromise – No Political Trading (1899)

"Interview de David Brin" at ActuSF.com (March 2008) http://www.actusf.com/spip/article-5739.html