Theo Todman's Web Page - Paper Abstracts

Author’s Abstract

1. On one familiar and very broad view of personal identity₁, the continued existence of a person over time admits of analysis in terms of relations of non-branching physical and/or psychological continuity².1 (One version of this view is the Psychological Criterion³, according to which A at t1 is identical to B at t2 iff A and B stand to each other in the relation of non-branching psychological continuity⁴.)
2. The need for a non-branching or no-competitors clause is occasioned by the most plausible description of the division or fission of persons, a situation in which one individual stands to each of two later individuals in qualitatively identical relations of physical and psycho logical continuity.
3. The inclusion of such a clause is necessary in order to avoid the consequence that the earlier person is identical to both resulting persons. The inclusion of a non-branching component in theories of personal identity over time has been thought to incur the charge of absurdity. The charge can be pressed as follows: any best-candidate⁵ theory of personal identity, which incorporates a non-branching component, violates a necessary constraint which governs our concept of strict numerical identity⁶ and - absurdly - implies, in a sense to be characterised, that the identity of a person over time can be extrinsically determined. Consequently, any best-candidate⁷ theory of personal identity over time is untenable.
4. If so, it follows that we must redescribe the transtemporal identities which hold in a case of division, e.g., along the lines suggested by Lewis, Perry and Noonan₈ (according to which the distinct post-division persons both occupy the single pre-division body), or else₉ give up entirely the attempt to analyse the identity of a person over time in terms of physical and/or psychological continuity¹⁰ (and embrace instead, e.g., Cartesian dualism). However, my ultimate aim in this paper is to show how commitment to the extrinsicness of identity on the part of best-candidate¹¹ theorists can be accepted without absurdity.