Curt Defends String Theory. Deutsch Destroys The Approach

String theory is criticized for its approach of finding mathematical objects before defining the physical problems they aim to solve, contrasting with effective scientific progress that starts with conceptual problems.

• Fundamental physics should begin with defining physical problems, not by exploring mathematical constructs.

• Mathematical breakthroughs, like those in string theory, do not automatically equate to progress in solving physical problems.

• David Deutsch maintains a 'wrong list' of innovations he underestimated, including Mathematica and X's community notes, due to their unexpected success in solving complex challenges.

David Deutsch argues against the methodological approach of string theory, contending that fundamental physics progresses by first identifying physical problems and then seeking mathematical solutions, rather than starting with a mathematical concept and trying to apply it to physics. He believes string theory has not solved any existing problems and questions its claims of progress, highlighting that effective research is problem-based and conceptual. Deutsch also reflects on his personal 'wrong list' of technologies he initially underestimated, such as Mathematica and X's community notes.

Critique of String Theory Approach

• 00:00:51 Progress in fundamental physics rarely comes from finding a mathematical object first and then wondering about its physical meaning; instead, it requires having an idea about the physical thing desired, like ensuring non-pathological commutation relations in quantum field theory, and then finding mathematics to achieve that. String theory takes the opposite approach, postulating fundamental strings and then exploring the resulting world, which David Deutsch believes is unlikely to succeed.

• 00:06:01 When string theorists claim progress through developments like ADS-CFT correspondence or holographic dualities, Deutsch maintains that mathematical progress is not necessarily evidence of being on the right track for solving physical problems. He contends that string theory has not solved any existing physical problem, and merely creating a framework where quantum mechanics and gravity coexist without mathematical contradictions is a mathematical achievement, but not necessarily a conceptual physical breakthrough.

• 00:09:08 A viable theory needs a conception of a problem and a proposed solution to that problem to precede it. In the case of string theory, Deutsch believes it has not solved any existing problems, instead hoping that some mathematics resembling existing frameworks will emerge with desired properties. He suggests that the 'renormalizability' problem string theory aims to fix might not even be a true problem, as infinities could potentially be a 'good thing' in an unknown future theory of quantum gravity.

The 'Wrong List' of Underestimated Innovations

• 00:13:50 David Deutsch keeps a list of significant advancements in fields where he initially doubted progress could be achieved, including the World Wide Web and natural language conversation with AI. Another entry on his list is Stephen Wolfram's Mathematica, which he believed could not create a general-purpose application interface that allowed users to define custom mathematical notation, a capability he found essential for his own work on quantum computers but thought impossible for a generalized tool.

Mathematica's Custom Notation

• 00:15:16 Deutsch's skepticism about Mathematica stemmed from his experience needing to write custom software to manipulate specific notations, such as 'Q matrix where Q was a function of T,' for working in the Heisenberg picture of quantum computing. He doubted a general-purpose program could handle the definition of arbitrary mathematical notations and their associated operations, but Mathematica proved him wrong by allowing such definitions, eliminating the need for him to write specialized programs.

• 00:17:22 The list also includes the laser guide star technique for telescopes, which Deutsch initially underestimated because he believed the atmosphere would affect the upward and downward laser beams equally, making effective correction seem marginal. However, this experimental physics technique significantly improved telescopic clarity, demonstrating a powerful idea he had initially dismissed.

Community Notes and Wikipedia's Evolution

• 00:19:03 David Deutsch initially doubted Wikipedia would work due to concerns about it being overwhelmed by spam and later, 'error' (what others might call bias), which he believed ultimately occurred, causing him to cross it off his list of successful innovations. Similarly, he expected X's community notes to fail due to the error correction mechanism itself being compromised by 'trolls and bad actors,' akin to a digital immune system being infected, but community notes has surprisingly made matters better, not worse, prompting its inclusion on his 'wrong list.'