Synchronic and diachronic identity for elementary particles
- PDF / 430,642 Bytes
- 17 Pages / 439.37 x 666.142 pts Page_size
- 2 Downloads / 231 Views
(2020) 10:33
PAPER IN PHILOSOPHY OF THE NATURAL SCIENCES
Open Access
Synchronic and diachronic identity for elementary particles Tomasz Bigaj 1 Received: 24 January 2020 / Accepted: 18 June 2020/ # The Author(s) 2020
Abstract The main focus of this paper is on the notion of transtemporal (diachronic) identity applied to quantum particles. I pose the question of how the symmetrization postulate with respect to instantaneous states of particles of the same type affects the possibility of identifying interacting particles before and after their interaction. The answer to this question turns out to be contingent upon the choice between two available conceptions of synchronic individuation of quantum particles that I call the orthodox and heterodox approaches. I argue that the heterodox approach offers a better explanation of the known experimental facts regarding particle interactions, and I probe deeper the concepts of synchronic and diachronic identity emerging from this approach. Keywords Diachronic identity . Synchronic identity . Individuation . Quantum particles .
Permutation invariance . Scattering experiments . Interference effects . Transition amplitudes
1 Introduction The problem of identity and individuality (discernibility, reference, etc.) in nonrelativistic quantum mechanics is typically considered in the context of instantaneous states of many particles of the same type. Given that at any moment the state of a system of such particles has to possess certain symmetry properties (it has to be either symmetric or antisymmetric), we may ask the question of how this fact affects the possibility of discerning the individual particles within the system, making reference to a selected subset of them, making sure that they are numerically distinct, and so forth. When answering these questions, we take a look at the momentary state of the involved particles, as if taking a snapshot of their history. We may call this perspective
* Tomasz Bigaj [email protected]; [email protected]
1
Institute of Philosophy, University of Warsaw, ul. Krakowskie Przedmiescie 3, 00-047 Warsaw, Poland
33
Page 2 of 17
European Journal for Philosophy of Science
(2020) 10:33
“synchronic”, as opposed to the diachronic perspective which compares states and properties of selected objects across different temporary instants. The issue of the diachronic identity and identification of quantum particles has received relatively little attention in the literature, apart from some general remarks regarding the non-existence of well-defined trajectories in quantum mechanics and the ensuing difficulty with tracing the temporal evolution of quantum objects.1 The current paper hopes to fill this gap. The terminological distinction between diachronic identity and synchronic identity may suggest, on a superficial reading, that we are dealing here with two distinct genera of identity relations. Indeed, some philosophers suggest that only synchronic identity is proper numerical identity, whereas diachronic identity is a different, albeit co
Data Loading...
