I Think, Therefore I Persist
Duncan (Matt)
Source: Australasian Journal of Philosophy, Volume 93, 2015 - Issue 4, Pages 740-756
Paper - Abstract

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Author’s Introduction

  1. Suppose that you’re lying in bed. You just woke up. But you’re alert. Your mind is clear and you have no distractions. As you lie there, you think to yourself, ‘2+2=4’. The thought just pops into your head. But wanting to be sure of your mathematical insight, you once again think ‘2+2=4’, this time really meditating on your thought.
  2. Now suppose that you’re sitting in an empty movie theatre. The lighting is normal and the screen in front of you is blank. Then at some point an image of a peach is flashed on the screen. The image isn’t up there for long. In fact, it’s only on the screen for what seems like an instant — just long enough for you to see it.
  3. These two scenarios are a bit mundane. But, as I will show, reflection on them can yield significant results concerning the nature of persons and their persistence through time.
    1. First I will show that thought and perception have temporal constraints whereby your thinking or perceiving in the above scenarios implies that you exist through a temporally extended interval.
    2. Then I will argue that this allows us to rule out several prominent theories of Personal Identity1.

  1. Thought and Perception
  2. Personal Persistence
  3. Conclusion

    1. Matt Duncan rightly claims that certain actions – those chosen being (logical) thinking and (visual) perceptions – take time to perform (for beings such as us). The reason being that our brains are somewhat sluggish – though presumably were they ever so fast, these actions would still take some time to perform.
    2. From these rather ordinary observations, Duncan deduces that “we” must persist during the period of their performance. Why should anyone quibble about this – though whether this argument has any implications for our longer term persistence is moot, and "Maurer (Nicholas) - Too Many Persons, or None At All?" takes Duncan to task on this account.
    3. More interesting from my perspective is Duncan’s claim that his TEs2 (when augmented to focus on the theories in hand) act as disproofs of certain popular theories of PID. My interest is focused on the alleged disproof of Animalism3.
    4. Later in the paper, Duncan is insistent that it’s important that the actions ensuring persistence are mental ones, though I’m suspicious that this may beg the question as to what we are4.
  1. Thought and Perception:
    1. Duncan gives a detailed account of his TEs. I have no reason to disagree here. I agree that thinking and perceiving5 take time.
    2. So, he comes up with his Thought Claim and his Perceptual Claim that – respectively – for you to think or perceive you need to persist for the duration of the thought or perception.
    3. He claims that his observation that “you” persist during these episodes does not rest on “you” being a Cartesian Ego6 or some such. Still, it takes time to kick a football, but he doesn’t use that sort of example.
  2. Personal Persistence:
    1. Duncan alleges that his two modest Claims have a significant philosophical pay-off in undermining popular theories of PID. He briefly outlines a couple7, involving physical or biological continuity. His aim is to come up with possible (if not plausible) scenarios arise in which your thinking or perceiving goes on but – by the lights of these theories of PID – you do not persist during the episodes, so contradicting his two Claims.
    2. He now spends a page setting up (what seems to be to me to be) a Straw Man – a “toy” theory of PID held by no-one – the combination of physicalism – the view that persons are wholly physical – and mereological essentialism – the view that a thing cannot survive the loss of any of its parts.
      • Well, it’s an easy task to show that a person subjected to such constraints would not persist from one second to the next, so would not persist long enough to think or perceive, so violating his two Claims. While no-one has ever held this hybrid view, he thinks it illustrates his argumentative strategy.
      • Interestingly, he does discuss mereological essentialism – of which he’s only discussing the 3D variant – in a footnote, and finds adherents8 though claims that such adherents are non-physicalists. He doesn’t discuss the possibility that a committed mereological essentialist9 might allow an object to become increasingly scattered10, though I doubt any such view would have much going for it.

  3. Conclusion:


In-Page Footnotes

Footnote 1: Footnote 5: Footnote 7: Footnote 8: Footnote 9: Footnote 10:

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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