A mathematician and a physicist were arguing over whose field of study was better. They decided to settle the argument by posing questions.
The mathematician went first, and posed a complicated mathematical problem.
With a great deal of effort, several books of mathematical tables and techniques, and a few hours, the physicist gave the solved problem to the mathematician, who was duly impressed.
"All right, my turn. Here's the problem: you have a pot of water on the stove, at 60 F. You want to heat it up to 70 F. What do you do?"
The mathematician replied, "Oh, that's easy. You turn the stove on. Fourier's equations govern how heat transfers from the stove to the pot, and you can solve them numerically to find out how long it takes for the water to reach 70 F."
The physicist then asks, "All right, so what if the water's at 65 F?"
"Oh, that's even easier. You take the pot of water, stick it in the refrigerator until it cools down to 60 F, and then it simplifies to the previous problem!"