What Is the Normal Explanation of Fire?

Ler's experiments demonstrated that both a gifted subject and a student volunteer could significantly raise and lower the temperatures inside sealed and heavily padded thermisters. But the effect was limited and involved relatively minor temperature fluctuations. So we don't have good evidence of psychic abilities being able to cause things, much less people, to burst into flame. If that were to happen, i would suspect it would be exceptional rare. I thus think our most promising explanations for this phenomenon would be natural.