EN
Pierre Duhem was first to undermine the possibility of conducting crucial experiments in science. Experiment, as he states, can neither verify, nor falsify any hypothesis - the choice of one theory over the other is not governed solely by facts. As is commonly stated, Duhem's results was amplified by Quine. The article discusses Quine's contribution to the considered issue and Lakatos' attempt to overcome the difficulties pointed out by Duhem and Quine which has resulted in a novel formulation of the demarcation problem.