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Letter: A better take on the anthropic principle?

Published 20 August 2025

From Derek Bolton, Sydney, Australia

Your article on how to think about the weak and strong anthropic principles (AP) took the Barrow and Tipler formulations. These conflict with the original Brandon Carter definitions, make much less sense and haven’t enjoyed much peer acceptance(28 June, p 32).

Carter’s weak AP is that within a universe capable of supporting intelligent life in some region and epoch, of course such life will find itself in such a Goldilocks circumstance – thus demolishing the “Copernican” assumption that our spot in the universe is typical. His strong AP is that if there is an ensemble of vast numbers of different universes, then we shouldn’t be surprised that some have such finely tuned constants.

Issue no. 3557 published 23 August 2025

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