The computer scientist who created the first chatbot and then spent his life warning us

Ideas & Philosophy · Published 3 October 2026 Swipe more like this →

In short: In the mid-1960s, Joseph Weizenbaum built Eliza, a program that mimicked a psychotherapist. He expected users to see it as a technical demonstration, but was shocked when they began treating the machine as a confidant. This experience turned him into one of the most prominent critics of artificial intelligence.

Joseph Weizenbaum, an MIT professor who fled Nazi Germany as a teenager, developed Eliza in the mid-1960s to demonstrate technical capacity. By scanning for keywords and using simple rules to generate responses, the program could simulate a Rogerian psychotherapist. Weizenbaum was alarmed to find that even short exposures to this simple software could induce powerful delusional thinking in normal people, a phenomenon now known as the Eliza effect. His secretary, for instance, asked him to leave the room so she could converse with the machine privately.

This realization shifted Weizenbaum’s career from technical innovation to philosophical inquiry. In his 1976 book, Computer Power and Human Reason, he argued that the debate over whether machines could truly think was irrelevant. Instead, he emphasized that the decision to assign tasks to computers is a human act rooted in values. He drew a sharp distinction between deciding—a computational process—and choosing, which he defined as a product of human judgment that cannot be automated.

Weizenbaum became a vocal critic of the field he helped pioneer, fearing that computers were fundamentally conservative forces that hindered social progress by automating existing systems rather than forcing necessary structural changes. He also remained deeply skeptical of the military’s influence on computing, arguing that the industry’s reliance on euphemisms like defense obscured the reality of its impact. By the time he moved back to Berlin in 1996, he had spent decades challenging the assumption that technological capability should be the primary driver of human progress.

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