Did the luminiferous aether theory aim to define absolute space, or at least a preferred frame of reference? From what I understand, the notion of frames of reference took precedence over a notion of "absolute space" in classical mechanics.
Did the luminiferous aether, aside from attempting to explain the behaviour of light, aim in any way to establish a preferred frame of reference ? It could seem to be a excellent candidate for defining an absolute space, although I can't find too much on the topic. Was establishing a "reference frame zero" of any interest at the time ?
 A: I don't think that the aether, in the 1880s, was thought of as providing, just by itself, a frame of reference. Newton's notion of absolute time and absolute space still prevailed. My understanding is that some considered that the aether was likely to be stationary relative to this absolute frame, and therefore, via M-M type experiments, might provide a practical way of finding out how (say) the Earth was moving in absolute space.
But of course the primary purpose of the proposed aether was to explain the propagation of e-m waves.
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Appendix: Extract from Scholium to Principia (revised Motte translation)
[...] I do not define time, space, place and motion, as being well known to all. Only I must observe that the common people conceive those quantities under no other notions but from the relation they bear to sensible objects. And thence arise certain prejudices, for the removal of which it will be convenient to distinguish them into absolute and relative, true and apparent, mathematical and common.
I Absolute, true, and mathematical time, of itself, and from its own nature, flows equably without relation to anything external, and by another name is called duration: relative, apparent, and common time, is some sensible and external (whether accurate or unequal) measure of duration by the means of motion, which is commonly used instead of true time; such as an hour, a day, a month, a year.
II  Absolute space, in its own nature, without relation to anything external, remains always similar and immovable. Relative space is some movable dimension or measure of the absolute spaces; which our senses determine by its position to bodies; and which is commonly taken for immovable space; such is the dimension of subterraneous, an aerial, or celestial space, determined by its position in respect of the earth. Absolute and relative space are the same in figure and magnitude; but they do not remain always numerically the same. For if the earth, for instance, moves, a space of our air, which relatively and in respect of the earth remains always the same, will at one time be part of the absolute space into which the air passes; at another time it will be another part of the same, and so, absolutely understood, it will be continually changed.
III  Place [...] [I omit, at least pro tem]
IV  Absolute motion is the translation of a body from one absolute place to another. Thus in a ship under sail, the relative place of a body is that part of the ship which the body possesses; or that part of the cavity which the body fills, and which therefore moves with the ship: and relative rest is the continuance of the body in the same part of the ship, or of its cavity. But real, absolute rest, is the continuance of the body in the same part of that immovable space, in which the ship itself, its cavity, and all that it contains, is moved. Wherefore, if the earth is really at rest, the body, which relatively rests in the ship, will really and absolutely move with the same velocity which the ship has on Earth. But if the earth also moves, the true and absolute motion of the body will arise, partly from the true motion of the earth, in immovable space, partly from the relative motion of the ship on earth [...] and if the body moves relatively in the ship [...]
