[Physics is] a good framework for thinking. … Boil things down to their fundamental truths and reason up from there.

Elon Musk has repeatedly described using “physics” or “first principles” reasoning as a personal problem-solving method, especially in interviews about how he approaches engineering and business decisions at companies like SpaceX and Tesla. The line about boiling things down to fundamental truths is typically presented as Musk explaining why he prefers to reason from basic constraints (materials, energy, costs, physical limits) rather than relying on analogy (“how it’s usually done”). The quote is widely circulated in business and tech media as a capsule summary of his stated approach to innovation and cost reduction, particularly in contexts discussing rockets, batteries, and manufacturing.

The quote frames physics less as a body of equations than as a discipline of thought: reduce a problem to what must be true, then rebuild solutions logically from those premises. Musk contrasts this with “reasoning by analogy,” where decisions follow precedent and inherited assumptions. The significance is methodological: it endorses skepticism toward conventional wisdom and encourages decomposing complex systems into fundamentals (e.g., raw material costs, physical feasibility) to uncover overlooked options. As a piece of entrepreneurial rhetoric, it also functions as a justification for pursuing seemingly implausible projects by treating them as engineering problems rather than social consensus problems.