An example of an historical scientific conception:
"…hypotheses may be of great value in science if they suggest new connections between facts, which lead to further experiments, even though these experiments ultimately show them to be untenable. The hypothesis of the ether, a medium filling the whole of space, is an example which illustrates this point. It was invoked to account for certain wave-like properties of light. Then Clerk Maxwell, developing mathematically the ideas of Faraday on electromagnetism, postulated a medium for the transition of electromagnetic effects. As he said, it was 'not philosophical' to invent a new medium, and when he succeeded in showing that disturbances in the electromagnetic medium would have a velocity equal to that of light in the luminiferous ether, he held it to be a strong reason for believing light to be an electromagnetic phenomenon, and the ether to be a 'reality'. The electromagnetic theory of light is one of the most fertile in physics, but the hypothesis of the ether has been discarded.
…in accounting for the radiation of heat across a vacuum such as occurs when the Sun warms the Earth, we might invoke an invisible medium, and call it the ether, and consider that radiant heat consisted of waves travelling through it. Such an ether would be an example of an all-pervading hypothetical body, and the waves would be hypothetical motions of its parts. Theories of this type have often proved of great value in science, especially when they can be developed mathematically so that deductions made from them can be tested accurately by means of measurements."
Brown, G. Burniston (1950) Science. Its method and its philosophy. London. George Allen & Unwin Ltd.
