Concentrate all your thoughts upon the work at hand. The sun's rays do not burn until brought to a focus.
Bell grasped something that sounds simple but proves devilishly hard to practice: scattered effort produces nothing, but *directed* effort produces heat. The metaphor works because it captures not just the need for concentration, but the *transformation* that happens when diffuse energy finds focus—a qualitative shift, not merely a quantitative one. When you're juggling email, a deadline, and three half-formed ideas, you're operating at the temperature of ambient light; the moment you corral your attention onto one thing, the rules of physics change. A surgeon closing a wound with full presence works differently than one mentally reviewing her grocery list, and the difference lives in that singular point of focus Bell describes.