Claude Bragdon A Primer of Higher Space: The Fourth Dimension

 

The fourth dimension offers a shock to the mind accustomed to practical handling of matter, because all our experiences of measurement or dimensionality are ultimately founded upon matter possessing but three dimensions, so that we have great difficulty in accepting the reality of a direction not contained in our space or our matter but definitely at right angles to every line that can be drawn within the matter and space which contain all our ordinary experiences.

Our idea of space is partial, and like many another of our ideas needs modification to accommodate it to fuller knowledge. 

What we think of as space is more probably only some part of space made perceptible. It may be that our space bears a relation to space in its totality analogous to that which the images cast by a magic lantern bear to the wall on which these images are made to appear—a wall with solidity, thickness, extension in other and more directions than those embraced within the wavering circle of light which would correspond to our sense of the cosmos.

In other words, perhaps that which we think of as space is only so much of it as our limited sensuous mechanism is able to apprehend.