duhem's idea was more subtle. he thought that for any given set of observations there is a huge and uncountable number of explanations. according to duhem, an experiment in physics is not just an observation, but an interpretation of observations by means of a theoretical framework. furthermore, no matter how well one constructs one's experiment, it is impossible to subject an isolated single hypothesis to an experimental test. instead, it is a whole interlocking group of hypotheses, background assumptions, and theories that is tested. this thesis has come to be known as holism. according to duhem, it makes crucial experiments impossible.