Profile of Physicist David Deutsch and His Contributions to Quantum Computing

The most significant developments in the sciences today (i.e., those that affect the lives of everybody on the planet) are about, informed by, or implemented through advances in software and computation. Central to the future of these developments is physicist David Deutsch, the founder of the field of quantum computation, whose 1985 paper on universal quantum computers was the first full treatment of the subject; the Deutsch- Jozsa algorithm was the first quantum algorithm to demonstrate the enormous potential power of quantum computation. When he initially proposed it, quantum computation seemed practically impossible. But the explosion in the construction of simple quantum computers and quantum communication systems never would have taken place without his work. He has made many other important contributions in areas such as quantum cryptography and the many-worlds interpretation of quantum theory. In a philosophic paper (with Artur Ekert), he appealed to the existence of a distinctive quantum theory of computation to argue that our knowledge of mathematics is derived from, and subordinate to, our knowledge of physics (even though mathematical truth is independent of physics). Because he has spent a good part of his working life changing people's worldviews, his recognition among his peers as an intellectual goes well beyond his scientific achievement. He argues (following Karl Popper) that scientific theories are “bold conjectures, ” not derived from evidence but only tested by it. His two main lines of research at the moment—qubit-field theory and constructor theory—may well yield important extensions of the computational idea. In the following essay, he more or less aligns himself with those who see human- level artificial intelligence as promising us a better world rather than the Apocalypse. In fact, he pleads for AGI to be, in effect, given its head, free to conjecture—a proposition that several other contributors to this book would consider dangerous. 84 HOUSE_OVERSIGHT_016304