How did G.E. Moore explain the claim that a person could have acted otherwise?

In the context of compatibilism, the philosopher G.E. Moore sought to reconcile determinism and free will by employing a conditional analysis of freedom.

Moore explained the claim that a person could have acted otherwise by stating that it simply means the individual "should" have acted differently "if" they had chosen to do so. Alternatively, he framed this as: "if I had performed a certain act of will, I should have done something which I did not do." Under this view, the fact that a person may not have been in a position to choose otherwise does not negate their free agency, as the ability to act freely is defined by this conditional relationship between one's choices and their subsequent actions.1