A remarkable real-life encounter between an American disability rights activist and a professor of bioethics at Princeton University is the spark for Christian O’Reilly’s new play for Once Off Productions, written in collaboration with Liz Carr, Mat Fraser and Olwen Fouéré.

After disabled lawyer Harriet McBryde Johnson (Carr) heard the Australian philosopher Peter Singer (Fraser) lecture in her home town of Charleston, South Carolina, in 2001, their email exchanges led to an invitation to address his students at Princeton. Accepting the challenge to respond to Singer’s advocacy of selective euthanasia of disabled babies and assisted suicide of disabled adults, it was as if she was being asked to justify her own existence, Johnson wrote in an influential New York Times Magazine article.

Incorporating excerpts from Johnson’s text, O’Reilly and co-directors Kellie Hughes and Fouéré have created a powerful verbatim theatre performance. Dramatising the Princeton event, it also explores the lived experience of disability with a light touch. As Carr and Fraser, playing themselves, comment on Singer’s theories, they delve into their own memories. Joking about the reactions of non-disabled people to them, their upbeat physical comedy turns into affecting reminiscences about love, sex and being truly “seen” for the first time.

Amid these multiple perspectives, some threads of the central arguments are not pursued, and need further probing. Singer’s points about the difficulty of life for severely disabled people and their families are countered by Johnson’s hope for more social equality to alleviate these pressures. For her, it is impossible for a non-disabled person to make a moral judgment on whether a disabled person’s life has value, since this is subjective.

She can’t think of Singer as a “monster”, because if she does, she would have to extend that label to many other people, which she refuses to do: a position that is rooted in her faith in human nature, or goodness perhaps. Perhaps she can’t allow herself to take his views completely seriously; “it’s just talk,” she says. Thanks to this immensely engaging production, there is going to be a lot more of that.