The Buddhist principle that all is empty is understood by some as the principle that all is relative (Thurman 1993). This universal relativity principle is more embracing though less structured than Einstein’s general relativity principle, which still admits many absolutes. The major changes in physics in this century have been extensions of relativity at one level or another, and I think a further extension is due, at an even deeper level of physics than the previous. Philosophical inquiry has aided such extensions before, and it could do so again. A philosophical argument for a universal relativity could be a useful guide for future physics.