Jordan Harrison’s play Marjorie Prime (Center Theatre Group, LA, 2014), a Pulitzer Prize finalist in 2015, depicts social, medical, and therapeutic interactions between humans and machines. In contrast to other contemporary plays, Harrison’s script does not suggest experimenting with real robots on stage, but follows the traditional approach of having actors pretend that they are machines or, more specifically, projections steered by an artificial intelligence, so-called Primes. The play carefully avoids the “uncanny valley” (Mori) and spares the audience visceral reactions to the machines, instead focusing on philosophical questions about identity, memory, language, and humanness. The article will analyse the use of language as a theatrical code for machineness and explore the implications of language as a criterion for machineness and humanness respectively. Marjorie Prime will be contextualized with the Turing test, especially from the angle of disability studies, to show how the play can be read as a critique of humanism and a plea for posthumanism.