William Newcomb and Robert Nozick have provided us with the following problem in rational decision-making. There are two boxes, A and B. A contains either a million dollars (M) or nothing (0). B contains a thousand dollars (T). I come into the room in which we have the boxes, closed. I must make one of two choices. Either I open A and take whatever money is present, M or O, or I open both and take whatever money is present, M + T or O + T. What is the rational choice for me to make?
Nothing unusual is meant by “rational” in this context. We assume that a person making the choice desires as much money as possible. We assume that he will take into account all relevant available information as to what decision will lead to more money. If he believes that doing X will, or is likely to, lead to more money than doing not-X, then he will do X.
In the above case, it would seem that the rational choice is both. T is there for the taking, whether or not I get M, and I might as well try for both.