W E E K 7 – W H Y D O W E D I S A G R E E A B O U T P E R S O N A L
I D E N T I T Y ?
R A S M U S P E D E R S E N - 2 0 2 4
PHIL2622
Reality, time, and possibility:
Metaphysics
Today
Why do we disagree about personal Identity?
4 / 2 2 / 2 0 2 5 S A M P L E F O O T E R T E X T 2

Theories of PI

• Physical continuity: PI is determined by the chain of physical similarities between persons, and any changes
in physical similarity relations between these persons are causally connected.
• Problem: The rotting corpse/zygote of a person is continuously physically similar to the living person,
yet not the same as the person.
• Psychological continuity: PI is determined by the chain of psychological similarities (beliefs, emotions, memory)
between persons, and any changes in psychological similarity relations between these persons are causally
connected.
• Problem: Genuine memory relies on PI definition; too many thinkers problem (human + animal thinker).
• Numerical identity (haecceity): PI is determined by numerical identity.
• Problem: Not definable
Today

What do people tacitly think that personal identity is?
Are we allowed to challenge what people think PI is?
If we ask questions about teletransporter thought experiments, memory transplant, etc, we can test whether
people hold a tacit psychological, physical, or numerical identity theory of personal identity.
Experimental folk-psychology

Condition 1
Memory removal + attitude/belief/desire
reversal
Future non-aestheticised surgery
Payment to avoid non-aestheticised surgery
Condition 2
No memory reversal
Future non-aestheticised surgery
Payment to avoid non-aestheticised surgery
Believes that
Physical continuity
is sufficient
Believes different PI
theory
but risk-averse and think
your PI theory may be
wrong
Result 1: No difference in payment in C1 and C2 Result 2: Difference in payment in C1 and C2
Do not believe physical continuity to
be sufficient. Believes psychological
continuity to be necessary
Test: Do people take the physical continuity theory to be sufficient for personal identity (PI)?
Experimental folk-psychology

Test: Do people take the physical continuity theory to be necessary for personal identity (PI)?
Condition 1
Teletransporter
Future non-aestheticised surgery
Payment to avoid non-aestheticised surgery
Condition 2
No teletransporter
Future non-aestheticised surgery
Payment to avoid non-aestheticised surgery
Believes that
Physical continuity PI
is not necessary
Believes physical
continuity to be necessary,
but risk-averse and thinks
PI theory may be wrong
Result 1: No difference in payment in C1 and C2 Result 2: Difference in payment in C1 and C2
Believe physical
continuity PI to be
necessary
Experimental folk-psychology´

Test: Do people take the psychological continuity theory to be sufficient for personal identity (PI)?
Condition 1: You are travelling to your favourite holiday destination (fill in), how do
you prefer to travel there?
Teletransporter ($20) (0.1% of failure) or Plane ($5.000) (0.1% of crash)
Believes that
psychological is
sufficient
Result 1: Choose teletransporter Result 2: Choose plane
Believe psychological
continuity to be
insufficient
Experimental folk-psychology

Discussion questions:
1. Does experimental inquiry into people’s tacit
beliefs tell us about what the correct theory of
PI is?
2. Are we allowed to challenge people’s theory of
PI through philosophical theorizing?
3. What if anything distinguishes philosophical
theorizing about PI from theorizing in physics?
What do we disagree about when we disagree about
theories of personal identity?
• Physical fact agreement
• Psychological fact agreement
• No further fact agreement (no haecceities)
Does the fact that we disagree matter if we cannot find any relevant facts we disagree about?
Are there any disagreements?
• We disagree about what our preferences in thought experiments are.
Different kinds of disagreements
Linguistic disagreement “Disagreement about what it means to ‘survive’”
• Does the discovery of the word's true meaning change views?
Conceptual disagreement “Disagreement about what the different concepts of PI theories mean”
• Does redefining the concepts or translating them into each other’s terms remove disagreement?
Grounding Disagreement “Disagreement whether PI is grounded by something and what grounds it”
• Does settling whether PI is grounded in something or not settle the debate?
Attitude Disagreement “Disagreement about how we react to people as being the same person”
• Can we agree on what it takes for a person to be recognized as the same or is this culturally relative?
Conativism about personal identity
Conative states: Non-truth apt mental states (desires, intentions, emotions, anticipations).
Cognitive states: Truth apt mental states (beliefs, reports).
Solution: Maybe what looks like cognitive beliefs about personal identity and survival are actually just conations
and are as such not truth-apt or not, they are experiential states that can be expressed in a belief like way.
• We adjust our beliefs to make sense of our conations, so that what we believe and what we feel are coherent.
• When we seem to be discussing beliefs, what we are discussing is actually the truth-value of different conations, but
conations are not truth-apt so there will be no way to settle who is right.
Conativism: Personal identity is satisfying desires, intentions, emotions, and anticipations about survival
Conativism about personal identity
Bad consquences of Conativism:
1. Same causes different effects (some survive the teletransporter others do not).
2. Survival is dependent on conations (can you change conations to change survival)
Any Questions?
Contact me by email:
rasmus.pedersen@sydney.edu.com

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