I think Marc might be referring to "navel gazing". If introspection is so important, we wouldn't need to do experiments to figure out what is reality. He could be advocating for Empiricism. You will find quotes like "If unsure, take a decision and make it right later. Don't get trapped in analysis paralysis". Basically two camps are fighting here : those who think reality can be figured out by thinking alone. and those who think we need to get out there and collect data and analyse it. I am personally biased toward Radical Conversatism.

Paul Dirac (1902–1984) was a British theoretical physicist and mathematician whose work on the Dirac equation (1928), which merged quantum mechanics with special relativity, predicted the existence of antimatter, specifically the positron. His approach to this discovery was deeply rooted in a mathematical philosophy that valued elegance, consistency, and a belief that nature is fundamentally mathematical, often placing him ahead of experimental validation.

Radical conservatism in physics, often associated with John Archibald Wheeler, is a philosophical approach that adheres strictly to established, successful principles—like quantum mechanics or general relativity—while pushing them to extreme, unexpected logical conclusions. It involves modifying as few laws as possible (conservative) while daringly following the math to radical insights.