The problem comes up because we ask the question in the wrong way. We supposed that solids were one thing and space quite another, or just nothing whatever. Then it appeared that space was no mere nothing, because solids couldn't do without it. But the mistake in the beginning was to think of solids and space as two different things, instead of as two aspects of the same thing. The point is that they are different but inseparable, like the front end and the rear end of a cat. Cut them apart, and the cat dies.
This is the great lesson that we are here to learn through myriads of births and heavens and hells - that there is nothing to be asked for, desired for, beyond one's spiritual Self (atman).
A man watches his pear-tree day after day, impatient for the ripening of the fruit. Let him attempt to force the process, and he may spoil both fruit and tree. But let him patiently wait, and the ripe pear at length falls into his lap.
Woman is fine for her own satisfaction alone. No man will admire her the more, no woman will like her the better for it. Neatness and fashion are enough for the former, and a something of shabbiness or impropriety will be most endearing to the latter.
The world is ready to give up its secrets if we only know how to knock, how to give it the necessary blow. The strength and force of the blow come through concentration.