The Nature of Physical Reality, Part II: Space

I met a traveller from an antique land,
Who said—“Two vast and trunkless legs of stone
Stand in the desert. . . . Near them, on the sand,
Half sunk a shattered visage lies, whose frown,
And wrinkled lip, and sneer of cold command,
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them, and the heart that fed;
And on the pedestal these words appear:
`My name is Ozymandias, King of Kings:
Look on my works, ye mighty, and despair!'
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare,
The lone and level sands stretch far away".
Percy Bysshe Shelley

Multiple instances of planar space

Space is the absence of anything. It may be one-dimensional, as for example, the space between words in a sentence; two-dimensional, as with a bullet hole in a signboard; or three-dimensional, like a hole in a Swiss cheese. But so far as we know, space cannot be more than three-dimensional, which puts the skids under string theory that demands five, six ... ten, eleven, or is it 25 dimensions of space. Time, moreover, although sometimes referred to as the fourth dimension, is not a spatial dimension but an index of the successive stages in the evolution of events in three-dimensional space.

End of infinite space ahead

Space, in other words, is everywhere that nothing else is. Thus, before the Big Bang, an observer with a flashlight would have seen that space was not only cold and dark but that, like the lone and level sands of Shelley's poem, it stretched far away, and indeed, if our observer's flashlight had been powerful enough, he would have seen that it stretched, boundless and bare, to the furthest corners of infinity (except that, with nothing to illuminate, the flashlight would have revealed nothing at all, not even the boundaries of infinity unless these were helpfully sign-posted).