Textbook of AI

1923–2008, Computer scientist; author of ELIZA

Joseph Weizenbaum was a German-American computer scientist at MIT who, in 1966, wrote ELIZA, a simple natural-language conversational program whose best-known script, DOCTOR, simulated a Rogerian psychotherapist by reflecting the user's statements back as questions ("My mother hates me." → "Tell me more about your mother."). ELIZA was a few hundred lines of MAD-SLIP doing little more than pattern-matching and template substitution; Weizenbaum was disturbed to find that users, including his secretary, formed real emotional attachments to the program and asked him to leave the room while they "talked" to it.

The reaction shaped Weizenbaum's later career as a philosophical and ethical critic of AI. His 1976 book Computer Power and Human Reason: From Judgment to Calculation argued that there are domains of human judgement, psychotherapy, the choice to wage war, the assignment of blame, where computer decision-making is not merely inadequate but morally inappropriate, regardless of technical capability. The book remains a touchstone of the philosophy and ethics of AI.

Weizenbaum was born in Berlin to a Jewish family and emigrated to the United States in 1936. He worked at General Electric on early banking-automation projects before joining MIT in 1963, where he remained until retirement.