Identity Over Time
Gallois (Andre)
Source: Stanford Encyclopaedia of Philosophy, 2005-11
Paper - Abstract

Paper StatisticsBooks / Papers Citing this PaperNotes Citing this PaperColour-ConventionsDisclaimer

Author’s Abstract

Irving Copi once defined the problem of identity through time by noting that the following two statements both seem true but appear to be inconsistent:

  1. If a changing thing really changes, there can't literally be one and the same thing before and after the change.
  2. However, if there isn't literally one and the same thing before and after the change, then no thing has really undergone any change.
Traditionally, this puzzle has been solved in various ways. Aristotle, for example, distinguished between “accidental” and “essential” changes. Accidental changes are ones that don't result in a change in an objects' identity after the change, such as when a house is painted, or one's hair turns gray, etc. Aristotle thought of these as changes in the accidental properties of a thing. Essential changes, by contrast, are those which don't preserve the identity of the object when it changes, such as when a house burns to the ground and becomes ashes, or when someone dies. Armed with these distinctions, Aristotle would then say that, in the case of accidental changes, (1) and (2) are both false—a changing thing can really change one of its “accidental properties” and yet literally remain one and the same thing before and after the change. Of course, this solution to the puzzle depends on there being a coherent distinction between accidental and essential changes, and between accidental and essential properties. Some philosophers find this distinction problematic and have developed other solutions that don't require this distinction. In what follows, we discuss these solutions to the puzzle, along with other puzzles that arise when considering the identity of objects over time.
  1. Introduction
  2. Identity and Change
    … 2.1 Diachronic and Synchronic Identity
    … 2.2 Identity as an Equivalence Relation
    … 2.3 Leibniz's Law1 and the Possibility of Change—The Problem of Temporary Intrinsics2
    … 2.4 Candidate Solutions
  3. Necessary and Determinate Identities
  4. Diachronic Identity Puzzles
    … 4.1 Constitution
    … 4.2 Relative Identity3
    … 4.3 Identity: ‘Strict and Loose’
    … 4.4 Arbitrary Undetached Parts
    … 4.5 Four Dimensionalism
    … 4.6 Temporary Identity4
    … 4.7 Further Puzzle Cases
  5. Personal Identity
    Academic Tools
    Other Internet Resources
    Related Entries


First published Fri Mar 18, 2005; substantive revision Thu Mar 17, 2011; Stanford Encyclopedia of Philosophy Archive: Identity Over Time.

Text Colour Conventions (see disclaimer)

  1. Blue: Text by me; © Theo Todman, 2020
  2. Mauve: Text by correspondent(s) or other author(s); © the author(s)

© Theo Todman, June 2007 - June 2020. Please address any comments on this page to File output:
Website Maintenance Dashboard
Return to Top of this Page Return to Theo Todman's Philosophy Page Return to Theo Todman's Home Page