Philosophy notes19

The issue is: Can we derive the laws of logic from psychology?

1.Psychology is an empirical descriptive science, whereas logic is both non-empirical and prescriptive. There is an inevitable gap between the two which cannot be filled in by experience. This difference has been recognized since Kant (in his critique of the project of rational psychology) and developed in a detailed way by Husserl in his Phenomenology and the Crisis of Philosophy.

2.The argument for deriving logic from psychology believes that psychology has a sanctity that is attained from its scientific status. Yet since Kant, there is a whole tradition that argues that science cannot proceed on exclusively empiricist premises. If we follow Kant, then the foundations of science cannot be termed as empirical. Science is founded on concepts such as substance, causation and reciprocity (the categories under the heading of modality). These are derived from logical judgements: categorical, hypothetical and disjunctive. There is an overlap between the judgments of logic and the concepts of science. The presuppositions of science, such as the Kantian categories, is termed by Kant as transcendental in the sense of being conditions that make experience possible. This aspect has been ignored by those who equate logic with psychology.

Whether we treat the categories as constitutive or regulative-they are transcendental.

3.Husserl has critiqued the phenomenon of psychologism that has been prominent among empiricists since Locke. Mill gave a clear statement endorsing psychologism: The laws of logic are derived from psychological processes. However, as Husserl argues psychological processes can be inconsistent and contradictory and cannot deliver the validity demanded by logic. In fact, to quote Husserl, “…all psychological knowledge in the ordinary sense presupposes essential knowledge of the psychical, and that the hope of investigating the essence of recollection, judgment, will, etc., by means of casual inner perceptions or experiences, in order thereby to acquire the strict concepts that alone can give scientific value to the designation of the psychical in psycho-physical statements and to these statements themselves-…” (118) 4.The strong apriori transcendental claims of Kant and Husserl have been opposed by Rorty and Quine with their project of naturalized epistemology. But linguistic postpositivist empiricism would not concede to first person reports as the foundation of logic or science. In fact, Quine, Davidson and Rorty (and Putnam) have all acknowledged that one needs to go beyond bare experience in the endeavor to make scientific statements.

Quine sums it all up with his two dogmas of empiricism: (1)the dogma of raw feels (2)the dogma of the divide between analytic/synthetic statements. Perhaps we can retain the insights of both Kant and Husserl regarding the distinction between psychology and logic in the light of these developments in post-positivist analytic philosophy.