Leiber's publications encompass a number of subjects, including philosophy, psychology, linguistics, and cognitive science. He published several papers on Alan Turing's Turing test and Turing's mathematical Turing machines and biological achievements, arguing that Turing Test passage requires actual, real time, reliable passage, thus excluding challenges to the Test by John Searle and others (Leiber 2006a, 1995, 1991) He also defends Turing's demand for a biology that excludes selectionist and functional explanations (Leiber 2006a, 2001) and he has offered a related critique of evolutionary psychology (Leiber 2008, 2006b). In several works (Leiber 1991,1988, 1975) he articulates the nativist and rationalist linguistics of Noam Chomsky. In a critical notice of Leiber's "Invitation to Cognitive Science", Diane Proudfoot and Jack Copeland comment that "He provides a rationale for the Turing test which knits together the motivational remarks of Turing's 1950 article more satisfyingly than any previously proposed and he draws attention to Turing's anticipation of connectionism in 1948." While acknowledging that Leiber's interpretation of Turing's 1936 paper is widely shared, they argue that this consensus "distorts both Turing's achievement and the epistemic status of the computational theory of mind." Proudfoot and Copeland also comment that "Leiber upsets the common view of Wittgenstein by arguing that theses in the "Philosophical Investigations" commit Wittgenstein to a scientific approach the mind and encourage a specifically computational theory of mind... central elements of Wittgenstein's constructive accounts of mind and language." However, they are critical of Leiber's audacious interpretation.