Non-defensible Middle Ground for Experimental Realism: Why We Are Justified to Believe in Colored Quarks

Abstract

Experimental realism aims at striking a middle ground between scientific realism and anti-realism, between the success of experimental physics it would explain and the realism about scientific theories it would supplant. This middle ground reinstates the engineering idea that belief in scientific entities is justified on purely experimental grounds, without any commitment to scientific theories and laws. This paper argues that there is no defensible middle ground to be staked out when it comes to justifying physicists’ belief in colored quarks, and that experimental realism shifts, under analysis, into scientific realism.