THE POWER OF THOUGHT EXPERIMENTS

According to popular opinion, thought experiments are limited in scope , since no novel empirical results could be expected to be produced by thought alone. Yet consider the spectacular 16th century experiment b y Stevin, leading to the discovery of the principles of the resolution and combination of forces. He conducted no experiments, for he derive d his novel and highly important conclusions by several steps of ingen ious reasoning alone. To understand why mental experiments may serve a s very effective scientific tools, we need to explicate carefully thei r underlying mechanism. Thought experiments invariably involve the wid ely debated notion of ''counterfactual conditionals.'' A variety of hi storical examples are offered designed to illustrate the nature of tho ught experiments, their associated counterfactual conditionals, as wel l a the nature of the vital link between the two.