Psychology and the a priori Sciences

Abstract

This essay explores the role of psychology in the philosophies of logic and arithmetic. It begins by reviewing the role of developmental psychology in a second-philosophical position on logic, with some attention to whether logical structure is fully represented, then draws this moral: because logic rests on our primitive cognitive mechanisms, we tend to think it couldn’t be otherwise; this explains why we imagine logic to be necessary when it’s actually contingent (e.g., failing in the quantum world). This account extends to elementary arithmetic (2 + 2 = 4), but the potential infinite shifts support from structures present in the world to a conceptual element rooted in the language-learning device. Each of us imagines that our intuitive picture of the infinite natural number sequence is shared and that it’s coherent, unique, and determinate, but the second moral from psychology is that these convictions are less secure than we tend to think.