psycho-logicn.

1912 F. C. S. Schiller Formal Logic xxiv. 393 Let him [sc. the formal logician] restrict ‘logic’ to what he means thereby. We shall merely..adopt another term. Let us call this other study Psychologic... Formal Logic may be left to its own devices henceforth, and Psychologic will study real knowing without impediment.

1931 N. Isaacs in Proc. Aristotelian Soc. 31 225 In my view..logic needs to be based on psychology through and through... That is the purport of ‘psycho-logic’: an expressly intermediate study that starts from clearly psychological facts, but examines these with logical intent, and attempts to show that a logic emerges from them, and of what kind.

1953 W. Mays & F. Whitehead tr. J. Piaget Logic & Psychol. iii. 25 These three difficulties force us to interpolate between psychology and axiomatic logic a tertium quid, a ‘psycho-logic’,..related to these in the same way as mathematical physics is related to pure mathematics and experimental physics.

1958 R. Abelson & M. Rosenberg in Behavioural Sci. 3 4/1 Such ‘reasoning’ would mortify a logician, yet it can be found in much this form inside of millions of heads. Thus we speak of the formal system as psycho-logic rather than as logic.

1963 Social Probl. 11 7 Psycho-logic encourages us to believe that our motives are always defensive and theirs are always offensive.

1976 World Politics 28 372 A second safeguard for intelligence analysts is to examine their attitudes for consistent or supporting beliefs that are not logically linked. These may be examples of psycho-logic.

1996 Philos. Sci. 63 33 A plausible (but false) suggestion is that our underlying psycho-logic involves deductive rules of inference.