An FT reader ignited a Big Bang on our letters page a couple of Saturdays ago, raising some intriguing questions about space-time – and sparking other readers to offer their thoughts on bosons and super-symmetry as well as chickens and eggs.

Kenyon Bradt from Muncie, Indiana lit the blue touch paper by asking about the “primordial locus” of the Big Bang:

Would it have had any spatial extension or temporal duration before the outburst? … Is it possible for there to be an existence that is non-spatial and non-temporal?

These are excellent questions for my favourite fictional theoretical physicist, Dr Sheldon Cooper. With two doctorates, a master’s degree and an IQ of 187, Sheldon is the ultimate uber-geek. If anyone can help Mr Bradt probe the nature of space and time it is Caltech’s dazzling prodigy, the frighteningly obsessive Nobel-prize-winner-in-waiting from “The Big Bang Theory”.

It’s just a shame that Dr Cooper always plays Klingon Boggle at this precise time of day, which means we must turn, for the time being, to real-life “quantum gravity” physicist Carlo Rovelli of Marseille. I’m sure you won’t be disappointed, though. Professor Rovelli’s ideas are quite startling enough.

Prof Rovelli says that time may not exist at all – at least at the quantum level. In an article by Tim Folger in Discover Magazine , he says: “It may be that the best way to think about quantum reality is to give up the notion of time – that the fundamental description of the universe must be timeless.”

Time, he says, could be an “emergent property” that comes into being only when you look at the bigger picture. (A good analogy is temperature, which doesn’t exist for an individual molecule but emerges as a collective property when lots of molecules bump around together.)

I can feel my inner Sheldon stirring, but Prof Rovelli hasn’t finished yet. In the article, he also does away with space:

If time and space are one day shown to consist of quanta, the quanta could all exist piled together in a single dimensionless point. “Space and time in some sense melt in this picture,” says Rovelli. “There is no space any more.”

So much for the final frontier, I hear Sheldon say - and just when I was putting the final touches to a grand unified theory of everything.

(Bazinga!)

Prof Rovelli’s theorising is only one way of interpreting quantum reality and, at first blush, killing off time and space may seem somewhat extreme. But it’s hardly unprecedented: you only have to look at the history of western philosophy. In several centuries of metaphysical thinking there’s a lot less to space and time than meets the eye. As often as not, both are explained – or explained away – in terms of our mentality.

Neither time nor space is substantial for Gottfried Leibniz. Rather similar to Prof Rovelli’s “single dimensionless point” is the “monad” – the non-extended, immaterial, indivisible entity that Leibniz believed to be the ultimate building block of the world; a mental atom.

For Immanuel Kant, space, time and causality are projections of our cognitive apparatus and have no reality independent of human experience. They are not part of the underlying nature of “things in themselves”, the noumenon, to which we can have no access.

Yet, according to Arthur Schopenhauer, who held similar views to Kant on space and time, there is a way to explore “things in themselves” – and that is to look inside one’s own self. He did – and claimed to glimpse ultimate reality in a unifying, homogeneous, ghastly impulse, which he called the “will”.

I suspect Sheldon would be kicking up a fuss at this point: “Oh dear Lord! Philosophical argument is no match for ‘Rock, paper, scissors, lizard, Spock’. Just think what these great men could have achieved if they’d spent less time navel-gazing and more time concentrating on comic books.”

(Dr Cooper is slowly unravelling the mystery of humour and sarcasm, which for him is much more difficult than string theory.)

There is a serious point here though … about whether in the 21st century we want to be materialists, idealists or dualists; and the relative importance we give to mentality.

Consciousness is a conundrum – both for quantum physicists (cf the much misunderstood Schrodinger’s cat) and for neuroscientists. Some of the latter are happy to equate consciousness with neuronal activity, but no one can yet explain why the physical firing of neurones should be accompanied by the subjective experience of awareness. “Why aren’t we zombies?” in the words of philosopher David Chalmers.

And consider this circularity. On the one hand we are told that our thinking arises in some unexplained manner from the activity of electrons in the brain synapses. On the other, electrons themselves are probability waves that exist as localised particles only when they are measured or observed – and what is observation but an act of consciousness?

So the nature of consciousness is wide open. Is it primitive? Or derivative? Or in some ways, both? (There may be different kinds, after all.) To my mind, mathematical thinking seems unchangeable, universal, elemental, fundamental, timeless; while our sensory notions of time and space could be “emergent” – but who knows from what?

What we think about consciousness will affect how we think about space and time. Kant talks of his own philosophy as a sort of Copernican revolution in reverse – putting human cognition at the centre of things. Both he and Schopenhauer agree that, without an observer, the universe is devoid of space and time.

But perhaps our misapprehension of existence goes even deeper.

In his ontological philosophy, Martin Heidegger says we have forgotten what it is to exist – what “being” is. Primarily, we are not subjects trapped inside ourselves looking out at a world of external objects. Rather, we are beings existing in a world of being. Most of the time we are too busy getting on with our activities to pay much attention to things like tables, chairs and door knobs. We pay them full attention only when things go wrong or we feel in contemplative mood. The rest of the time such objects have a sort of transparency for us.

Now that I’ve had my mind expanded by Leibniz, Kant, Schopenhauer and Heidegger, not to mention Sheldon, the Big Bang seems rather beside the (single, dimensionless) point unless hooked up to our present perception and thought. If our universe existed on its own for several billion years before conscious life, it lacked the reference points that human minds bring to it: there was no sense of relative scale; or of time passing. Time might as well run through such a place all at once – on extreme fast-forward.

Did the Big Bang make a noise? This is a cosmological variant of that ancient puzzle, “When a tree falls over in the woods and nobody’s there, does it make a sound?”

The answer to the Big Bang version of this question is “Yes” … but only because we are still “hearing” the noise today in the form of background microwave radiation. I’ve always been convinced that the answer with respect to trees is “No”, provided no one left a recording device in the woods.

So back to Mr Bradt’s primordial questioning. Is it possible for there to be an existence that is non-spatial and non-temporal? I’d say that, even though we sometimes think spatially, any idea “inside” our minds – such as “justice”, “pi” or “Sheldon’s mother” – is not actually extended in Euclidean space or in non-Euclidean space-time. Yet our non-extended minds somehow endow the universe with extension, duration and scale as well as separateness or objectivity. The world “out there” is neither big nor small, old nor young, except for our perception. Take our emergent sense of appearances out of the equation and space-time loses its scaffolding, like closing a children’s pop-up book.

I hope you had a happy “Star Wars Day” yesterday, Mr Bradt. May the 4th be with you!