I'm having a difficult time rationalizing the description that a book I'm currently reading has given of Newton's idea of acceleration relative to absolute space. As I understand this description, it states that acceleration occurs relative to the whole of absolute space. I don't understand how one can make this statement, for it is not known, as far as I am aware, whether or not space is finite. If space is infinite, how can can one make the statement that any state of motion during acceleration is any faster or slower than any other state of motion during acceleration? Acceleration requires a reference point just as well as any other state of motion, but a reference point would be meaningless in an infinite plain. Any one reference point is just as good as any other. The reference point could very well exist at any and all points during an objects acceleration. Unless it were given a relative position to some other reference point within space, in which case it would be distinguishable from any other reference point. It would make sense to me to say that acceleration occurs relative to the point of the origin of the force, rather than to an undefinable point in absolute space; such as the point at which an astronaut in space turns on his jet pack and starts accelerating, or a point in space that the axle of a rotating wheel takes up. In this case, two distinguishable reference points are given: the point of the origin of the force, and the point that is the accelerating object. But this still doesn't make sense, because each of the reference points could appear to be accelerating relative to the other, even though only one of them is. This only really makes sense to me if space is given to have parameters and to be definably still (if the properties of absolute space can't be measured or observed, then what's to say that it isn't also undergoing some state of non-uniform motion?), thus making reference points distinguishable. I suppose one could argue that the whole of infinite space could be considered a parameter, but I don't personally believe that such would validly explain this dilemma. So, is there anyone who could please help clear up my confusion?