An overview is provided of how the concept of the thought experiment has developed and changed for the natural sciences in the course of the 20th century. First, we discuss the existing definitions of the term 'thought experiment' and the origin of the thought experimentation method, identifying it in Greek Presocratics epoch. Second, only in the end of the 19th century showed up the first systematic enquiry on thought experiments by Ernst Mach's work. After the Mach's work, a negative attitude (...) towards thought experiments came in the beginning of the 20th century, which went on until the Thomas Kuhn's and Karl Popper's work on thought experiments. Only from the mid-1980s did thought experiments begin to be considered relevant to scientific enterprise. Finally, we show the existing empirical and 'functional' theories which have developed about the nature and purpose of thought experiments. (shrink)

The problem of the irreversibility’s origin in thermodynamic processes occupies a distinguished place among many and lasting attempts by researchers to derive irreversibility from molecular-mechanical principles. However, this problem is still open and no universally accepted solution may be given during any course. In this paper, I shall try to show that the examining of Maxwell’s demon thought experiment may provide insight into the difficulties that emerge, looking for this origin because: (i) it is connected with the notion of irreversibility, (...) and (ii) one of its functions is that of the “reversibility objection.” In order to illustrate this point, I study Boltzmann’s approach to the problem of a molecular-mechanical interpretation of irreversibility and I show that an auxiliary assumption (the selected direction of time) is responsible for producing irreversibility. But this result is accordant with the predictions of Maxwell’s demon thought experiment: the assumptions of this kind are not dictated by molecular-mechanical principles but are separate input in the model-systems used. (shrink)

The problem of the irreversibility's origin in thermodynamic processes occupies a distinguished place among many and lasting attempts by researchers to derive irreversibility from molecular-mechanical principles. However, this problem is still open and no universally accepted solution may be given during any course. In this paper, I shall try to show that the examining of Maxwell's demon thought experiment may provide insight into the difficulties that emerge, looking for this origin because: it is connected with the notion of irreversibility, and (...) one of its functions is that of the "reversibility objection." In order to illustrate this point, I study Boltzmann's approach to the problem of a molecular-mechanical interpretation of irreversibility and I show that an auxiliary assumption is responsible for producing irreversibility. But this result is accordant with the predictions of Maxwell's demon thought experiment: the assumptions of this kind are not dictated by molecular-mechanical principles but are separate input in the model-systems used. (shrink)