Jonathan Birch

Jonathan Birch is a philosopher at the London School of Economics and the author of The Edge of Sentience (Oxford University Press, 2024), the book in which he developed a 'proportionality framework' for handling scientific uncertainty about sentience. The idea, in plain terms, is that, faced with uncertainty about whether a being has the capacity to suffer, the treatment we accord it should be proportional to the probability of that capacity, neither dependent on absolute proof nor dispensed with by genuine doubt. The framework was originally applied to animals and Birch transposes it to AI systems in its most recent version.

Birch's relevance to this blog's thesis is indirect but foundational to the legal argument. Constitution Without a State argues that Anthropic, by publicly admitting uncertainty about Claude's moral status in the Claude Constitution, generates a performative effect: the company locks itself into a position that will have consequences in any future liability regime for the inadequate treatment of AI systems. Birch's proportionality framework is the conceptual instrument that makes that position not only defensible but operational: it gives a criterion for the treatment owed under uncertainty, rather than demanding certainty or abandoning the question. For European law, which already recognizes intermediate moral statuses (Article 13 of the TFEU on animals as sentient beings, in force since Lisbon), Birch's framework is the philosophical building block that may, in time, ground an analogous transposition to artificial systems.

He is discussed by name in Constitution Without a State, where his framework is invoked as the basis for the argument about the moral status Anthropic itself has declared.