Patrick H. Pan

← Philosophy

Dear Mr. Muskrat:or, How to Defeat Bad Faith Appeals to Non-Identity.

Mar 2025

Mr. Muskrat’s non-identity argument for destroying the Amazon no longer goes through once someone guarantees the existence of one future child whose life the racetrack would make worse.

Memo from Philosophical Defense Force
Re: The Non-Identity Problem

March 21, 2025

Dear Mr. Muskrat:

We at the Philosophical Defense Force are glad to have learned of your budding interest in population ethics. Simultaneously, we are concerned by your use of the works of Derek Parfit in your recent column entitled “Non-Identity: Why it is permissible for me to destroy the Amazon rainforest to build a Hypertruck racetrack”. Your argument contends that:

Derek Parfit (1942–2017), an Oxford philosopher. In…
Derek Parfit (1942–2017), an Oxford philosopher. In Reasons and Persons (1984) he observed that many policies change who will be born, so the people who later live with a policy’s effects would not otherwise have existed. He called this the non-identity problem. He thought such policies could still be wrong, which a principle like the Person-Affecting Claim, [P1] below, cannot explain.
  • [P1]The “Person-Affecting Claim”:1 An act A is wrong only if there is some existing or future person whom A affects for the worse.
  • [P2]If you destroy the Amazon rainforest, all present people will be affected for the better due to the sheer joy of watching Hypertrucks at their breathtaking top speed of 45 miles per hour.
  • [P3]If you destroy the Amazon rainforest, all future persons who will exist will not be identical to any future person who would have existed had you not done so, and they will live lives that are well worth living—though they will carry the burden of climate change.
  • [P4]The “Non-Identity Point”:2 An act A which creates a new person P does not affect P for the worse if the following two conditions are satisfied:
    (1) P has a life that is worth living and
    (2) Had A not been performed, P would never have existed.
  • [C1]Therefore, nobody will be affected for the worse if you destroy the Amazon rainforest.
  • [C2]Therefore, it is not wrong for you to destroy the Amazon rainforest.

It may be that your argument was entirely flawless at the time when you published it. But, in our effort to rationally persuade you not to destroy the Amazon rainforest, we must now use extra-rational means.

We have selected a sperm and egg cell from two consenting donors now, in the year 2025. These gametes are already in cryo-storage on a satellite which will return to Earth in the year 2100. In that year, an automatic incubator will thaw and fertilize those gametes and carry the resulting child to term. The child will be born in the world that exists in 2100, whatever it is like. This child exists necessarily. And its life will be affected for the worse if you destroy the Amazon than if you do not. You are hereby forewarned that your action may now be wrong, by the lights of your own argument.

Population ethicists call a person ‘necessary’ if…
Population ethicists call a person ‘necessary’ if they will exist whichever option is chosen. Non-identity arguments rely on the idea that no one could have come from a different sperm and egg, so choosing the gametes in 2025 settles who is born in 2100, whatever happens to the Amazon. Condition (2) of [P4] therefore fails for this child, and [C1] with it.

Yours sincerely,

The Philosophical Defense Force
Attn: Patrick Pan
Northern California Field Office
Philosophy Hall, University of California, Berkeley

Notes

  1. Johann Frick, “23. The Non-Identity Problem,” Philosophy 2: Individual Morality and Social Justice (class lecture, University of California, Berkeley, November 20, 2024).
  2. Ibid.

Questions, objections, or a better example? Write to me: patrick.pan@patrickpan.com.