Plantinga’s Replacement Argument
Van Inwagen (Peter)
Source: Baker (Deane-Peter) - Alvin Plantinga, Chapter 8
Paper - Abstract

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Author’s Introduction

Alvin Plantinga has recently turned his attention to materialism. More precisely, he has turned his attention to the thesis that philosophers of mind call materialism. This thesis can be variously formulated. In this essay, I will take “materialism” to be the conjunction of the following two theses:

  1. Human persons – what human beings refer to when they use the first-person-singular pronoun – are substances. They are substances in the strict and philosophical1 sense: They persist through time, retaining their identities while changing various of their accidental properties; they are not grammatical fictions; they are not “modes of substance”; they are not logical constructs on shorter-lived things (they are not entia successiva); they are not abstract objects (they are not, for example, things analogous to computer programs); they are not events or processes.
  2. These substances, these human persons, are wholly material. They are (if current physics is to be believed) composed entirely of up-quarks, down-quarks, and electrons, so related by the electromagnetic and color forces as to compose matter in its solid, liquid, and gaseous phases. They are, in two words, living organisms – or, if not whole living organisms, then parts of living organisms (human brains, brains-plus-central-nervous-systems, brain stems, cerebral hemispheres, cerebral cortices – or perhaps even luz bones or tiny, almost indestructible material things unknown to physiology …). They have no immaterial part.

Van Inwagen’s (hereafter PVI) paper is a rebuttal of an argument in "Plantinga (Alvin) - Against Materialism". My comments below are brief reminders of the main points of Van Inwagen’s paper. See the paper itself (Link (Defunct)) for more detail.

  1. PVI is a proponent of (and Plantinga – hereafter AP – an opponent of) Materialism in the Philosophy of Mind.
  2. PVI takes it that Materialism in this sense consists in the acceptance of two propositions:-
    • P1: Human Persons are2 substances.
    • P2: These substances are wholly material.
  3. Both3 PVI and AP accept P1.
  4. PVI accepts, but AP rejects, P2.
  5. The version of P2 under consideration – the version that PVI accepts – is that I am identical to my body.
  6. Plantinga considers the rejection of P2 of great human importance, while PVI considers its acceptance only of great philosophical importance – provided only that its rejection doesn’t undermine the acceptance of the Christian doctrine of Resurrection. PVI doesn’t address the issue of the alleged human importance of P2 in this paper.
Section 1
  1. PVI’s paper addresses Plantinga’s “Replacement Argument” from Section I of "Plantinga (Alvin) - Against Materialism". PVI summarises the argument – which comes in “micro” and “macro” versions, though PVI only directly addresses the “macro” version. “Macro” refers to the replacement of large body parts, “micro” to the replacement of cells.
  2. The argument alleges that “I” could be continually conscious (and therefore4 exist throughout) a procedure wherein the various parts of my body are serially and rapidly replaced.
  3. The difficult part of this (supposedly metaphysically possible) procedure assumes the (metaphysical possibility of the) idempotency of the cerebral hemispheres, and the metaphysical possibility of “transferring” the mental functions from one hemisphere to the other while the former is replaced (and then back again, when the other will be replaced).
  4. Both PVI and Pl agree that B (the body) does not survive the part-replacement process.
  5. Since (the argument goes) B does not survive, but I do (as there is a single conscious experience throughout the process (it is claimed)), then I am not identical to B.
  6. To be continued …

Section 2
  1. To be supplied …

Section 3
  1. To be supplied …

Section 4
  1. To be supplied …

  1. To be supplied …


Van Inwagen's website: published in "Baker (Deane-Peter) - Alvin Plantinga"; Link (Defunct); annotated hard-copy filed in "Various - Papers on Identity Boxes: Vol 18 (T-V)".

In-Page Footnotes

Footnote 2: Footnote 3: Footnote 4: The logic of this claim needs to be carefully considered. It (most likely) presupposes that “I” am a fundamentally psychological being, a claim denied by the animalists.

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)

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