"Science sometimes improves hypotheses and sometimes disproves them. But proof would be another matter and perhaps never occurs except in the realms of totally abstract tautology. We can sometimes say that if such and such abstract suppositions or postulates are given, then such and such must follow absolutely. But the truth about what can be perceived or arrived at by induction from perception is something else again. (...) Prediction can never be absolutely valid and therefore science can never prove some generalization or even test a single descriptive statement and in that way arrive at final truth. (...) It follows that what we, as scientists, can perceive is always limited by threshold. That is, what is subliminal will not be grist for our mill. Knowledge at any given moment will be a function of the thresholds of our available means of perception. The invention of the microscope or the telescope or of means of measuring time to the fraction of a nanosecond or weighing quantities of matter to millionths of a gram - all such improved devices of perception will disclose what was utterly unpredictable from the levels of perception that we could achieve before that discovery. Not only can we not predict into the next instant of the future, but, more profoundly, we cannot predict into the next dimension of the microscopic, the astronomically distant, or the geologically ancient. As a method of perception - and that is all science can claim to be - science, like all other methods of perception, is limited in its ability to collect the outward and visible signs of whatever may be truth. Science probes; it does not prove".
Gregory Bateson - Mind and Nature: a necessary unity