Maren Bräutigam
University of Cologne
In this paper, I discuss the ambiguity problem which befalls the heterodox view on the qualitative identity/difference of similar particles, such as two electrons. According to the heterodox view, similar particles are (almost always) qualitatively distinct, so that Leibniz’s Principle of the Identity of Indiscernibles is valid (this view contrasts with the orthodox view, according to which the opposite is the case). Tomasz Bigaj has argued that the worst problem for the heterodox view (whose ultimate solution is yet to be found) is the ambiguity problem, according to which individuation via properties is not unique. I argue that two different kinds of ambiguity, namely interbasis-ambiguity and intrabasis-ambiguity, should be distinguished. I propose a new criterion for dealing with both kinds of ambiguity, which I call the measurement approach. According to the measurement approach, properties individuate particles iff they count as physical. A property counts as physical, in turn, iff it can (in principle) be registered by a measurement device. I argue that, in comparison to other approaches which have been proposed so far, the measurement approach solves more cases of ambiguity in an easier way. However, since some cases of intrabasis-ambiguity remain unsolved, intrabasis-ambiguity is the hard problem for the heterodox approach.
Chair: Niklas Parwez
Time: September 11th, 17:00 – 17:30
Location: SR 1.004
SOPhiA 2026 