Abstract

Theories are ordered along a temporal line: there are past and present theories. Theories may be speculative but a large number of them are not the result of idle speculation. Theories can take many different forms but they are usually an attempt to solve some kind of problem. If theories are juxtaposed on a temporal or historical line, and if they are matched against some corresponding problems, then those problems, too, exist on a temporal line. Of course, this is not a one-to-one correspondence; a number of theories may be submitted, at a certain time t1, to answer a given problem; also theories that are separated on the temporal line, i.e., that are historically apart, may still concern some broadly identical problem p1 whose identification and formulation may either be imagined as fixed at, say, t1 and subsequently to survive as such, or as recurring, in different versions, at t2 … t4 etc. on our historical line. But is this alternative a real one? Theories evolve, and so does the perception of problems. In which sense can any two historically separated theories T1 and T2 be said to relate to the same problem p1? And what does it mean to speak of the same problem if the perception and formulation of a problem is at least partly dependent on the way it is stated in T1 and T2 respectively?