According to M-theory as I understand, the 7 additional spatial dimensions to our familiar 3 are curled up all around us but they are too small for us to see. However I have difficulty in understanding how this constitutes a "dimension" because dimensions allow additional degrees of freedom. I understand Rob Bryanton's view of it which explains how (and this is my brief interpretation) each extra dimension is reached by folding the current one. Ie fold a '2D' piece of paper into the '3D' dimension and you get a '3D' object. So in a sense each dimension is fundamentally "extra" and allows instantaneous movement from one point to another in the dimension below. But this version of extra dimensions seems to differ entirely in that if I were to fold 4D spacetime into the 5th dimension, and entered that dimension, I should be able to move instanteously to any other point in the 4th dimension, so thereby having free access to go to any point in my current timeline. Whereas M theory's extra dimensions doesn't seem to make sense. Put another way, if you pretend a straw is one of these curled up dimensions, the fact that I am able to trace a path around the curved surface doesn't mean I am suddenly moving in a different dimension from 3 space. And if the straw kept getting smaller and smaller, it would be still be occupying 3 space... would it not...?