Game theory
The mathematical study of strategic decision making and behaviour amongst interactions between rational agents. Here, the rational agent is rational because they perform the optimal actions in light of the information they have, where what is optimal depends on the context, e.g. maximizing long term profit is optimal in the neoclassical economic sense.
Thoughts
The work of Kenneth Binmore on relating game theory to morality, and how he brings together John Rawl's maximin principle and John Harssanyi's view of utilitarianism seems important enough to carefully read.