Many philosophy problems involve imagining hypothetical scenarios. At times there has been significant debate over the validity of this.
At times there has been significant debate on Less Wrong about the relevance or value in discussing hypotheticals.
Hypotheticals are essentially the same as counterfactuals, although a) the term counterfactual is preferred when imagining someone making different decisions b) technically the factual isn't a counterfactual, but it is very common to say something like "iterate over all the counterfactuals and pick the one with the highest utility" where we treat the factual as a counterfactual.