IS PURE THOUGHT WORK OR NO WORK?
Can a "thinking only" Big Brain or Propeller Elf do work? The scenario: a Propeller Elf is given a thinking program, as in calculating a non ending progression of numbers, that continues forever to think, as long as the power is applied within the closed system as a whole. It may become a pseudo perpetual motion or perpetual thinking machine. In this case, is work being performed? It depends on the program and the definition of work. Taking the Physics definition of work, a program that loops, and moves processor bits from point A to point B and back again, is doing no work at all, regardless of how many times it completes full loops. If the code moves processor bits from point A to point B which don't return, work is accomplished. In physics, mechanical work is a scalar quantity that can be described as the product of a force times the distance through which it acts, and it is called the work of the force. In the Prop Elf, the scalar quantity of bits that do mechanical work (become a 0 or a 1) traverse distance through the propagation of electrons in the chips substrate. The conclusion is, the Prop Elf may have two different types of thinking programs, one which is doing work and one that does no work, by definition. One thinking program can also terminate in one state or another, designating work or no work.
Reference
http://en.wikipedia.org/wiki/Work_(physics) If a constant force of magnitude F acts on a point that moves d in the direction of the force, then the work W done by this force is calculated W=Fd.