What if we want to know more about counterfactuals? How experiments, thought experiments and computer simulations help gain knowledge about counterfactual conditionals

Experiments, thought experiments and computer simulations are often used to study counterfactual scenarios. The respective results may thus be summarized in terms of counterfactual conditionals, which become at best the object of new knowledge. But how exactly do these methods help establish knowledge of counterfactuals? To answer this question, the talk starts from a few examples in which scientists have claimed to obtain knowledge of counterfactuals by means of the methods. Cotenability views of conditionals and a possible-world semantics for counterfactuals are used to explain what counterfactuals mean. The question then is how experiments, thought experiments and computer simulations can at least make a case for believing such counterfactuals. Assuming that experiment is the least controversial method among the three, it is briefly explained how experiments can help gain knowledge about counterfactuals. I then use my examples and the semantic considerations as a testing ground for some prominent epistemologies that have been suggested for thought experiments and computer simulations, respectively. A particular focus is on matters of validation. A two-fold benefit is hoped for: First, some accounts of thought experiments or computer simulations may do better than others in view of the counterfactuals. Second, the hope is that this exercise in comparative epistemology allows for a clear appreciation of the similarities and differences between the three scientific methods