Showing posts with the label Comments on

Steven Weinberg's mistakes

Experience shows that some people likes to rewrite history and make heroes, and when Steven Weinberg died in 2021, some obituaries could not resist the temptation. In 2005, Weinberg wrote an article titled "Einstein's Mistakes". I am not Weinberg and he was not Einstein, but I will write about Weinberg's mistakes in this post. Weinberg justified his review [1] of Einstein's mistakes in the following terms: "Perhaps most important, by showing that we are aware of mistakes made by even the greatest scientists, we set a good example to those who follow other supposed paths to truth. We recognize that our most important scientific forerunners were not prophets whose writings must be studied as infallible guides—they were simply great men and women who prepared the ground for the better understandings we have now achieved". I will not review all of Weinberg's mistakes, but only those which appear in the obituary written by Nima Arkani-Hamed: "How St

Comments on symmetric monoidal categories by John Baez

I recently watched a talk by John Baez titled " Symmetric Monoidal Categories " [1]. Baez presents new mathematical material that he considers provides a common foundation for the description of different scientific and engineering topics, material that he considers to be a kind of " Rosetta stone ". Baez is correct that scientists and engineers like to describe processes or composite systems using diagrams: flow charts, Petri nets, electrical circuit diagrams, signal-flow graphs, chemical reaction networks, Feynman diagrams, etc. He claims that many of these diagrams fit into a common framework, the mathematics of symmetric monoidal categories, and that when we accept this achievement, we begin to see connections between seemingly different topics. Baez also claims that this new viewpoint introduces a paradigm shift in science. Let us go over all those interesting claims. My comments will focus on the scientific side of his talk. To get started, Baez says that s