Another account of ‘could have done otherwise’ makes use of the concept of sufficient antecedent causal condition. We might think that when we say that someone could have gone to Boston instead of staying in Providence, what we mean is merely that at some earlier time this morning, his trip to Boston was causally indeterminate — there was no sufficient causal condition either for his going to Boston or for his not going to Boston. Chisholm argues against this idea, too. Suppose another person was lying in wait in Chelmsford. Suppose this other person would have freely interfered with our man’s travel plans if he had tried to get to Boston. Then it would not be correct to say that the man could have gone to Boston, but it would have been correct to say that there was no sufficient causal condition then in place that would have prevented the trip. The relevant sufficient causal condition would not have arisen until the person lying in wait in Chelmsford had freely interfered.