Is everything ‘spacetime’?

For a couple of weeks I’ve been trying to elicit responses on the Objectivism Online Forum…

…specifically to John A Macken’s The Universe is Only Spacetime: Particles, Fields and Forces Derived from the Simplest Starting Assumption (mentioned on last month’s blog). I was fishing for opinions from those with much more of a bent for hard-core physics than I.

Fundamentally, is there only ‘spacetime’? 

This was my initial question and title of the thread, but I came to realise that it required unpacking,
and eventually needed re-writing in order to shed certain inherent presuppositions.


Hereunder is essentially the same question, yet drawn out in a more self-explanatory way:

Could the mechanics of the universe be adequately described using a dynamic conjunction 

of space and time ~ ‘Macken Spacetime’ ~ without referring to any extra ‘stuff’?

So far there hasn’t been that much engagement with Macken’s ideas directly, but the thread is on-going for anyone who wants to add anything. It has helped somewhat to crystallise my views in preparation for an up-and-coming summary of all my metaphysical musings, earmarked for later this year.


Anyway, here's a link to Macken’s book in order to read how his ‘spacetime’ differs from the current standard notion.

It's certainly a fascinating idea, one I'd like to develop further, but do you think Macken's physics and metaphysical assumptions stand up?