Useful Counterfactuals

Counterfactual conditional sentences can be useful in artificial intelligence. In particular, they allow reasoners to learn from experiences that they did not quite have. The truth of a counterfactual and the conclusions that can be drawn from a counterfactual are theory dependent, and different theories are useful in different circumstances.A simple class of useful counterfactuals involves a change of one component of a point in a space provided with a cartesian product structure. We call these cartesian counterfactuals. Cartesian counterfactuals can be modeled by assignment and contents functions as in program semantics. We also study the more general tree-structured counterfactuals