The question is often posed (and likely has been since questions were invented), "Why is there something rather than nothing?". This question has special philosophical and religious importance and of course I am not about to suggest that I am in any position to provide a definitive answer. With that said, I must admit that I find the question a peculiar one. In order to explain why, a slight diversion is required.
I have typically reserved this blog for musings of a strictly philosophical nature in the past, especially with regards to ethics. However, physics is my trade, and my original intention was never that the blog was to be exclusively philosophical. It is therefore with no guilt (but plenty of fore-warning) that I am about to introduce an element of physics to this particular musing, and I will have to ask that the less scientifically-minded of my readers bear with me as I will try to keep things as simple as possible.
In the popular literature one of the more commonly referred to principles of quantum mechanics is the Heisenberg Uncertainty Principle, which is commonly expressed as meaning that a particle's position and momentum cannot be simultaneously known to arbitrary precision or, as it is usually misleadingly rendered: one can either know a particle's position but not its velocity, or its velocity but not its position. Mathematically this is understood by the equation ΔxΔp ≥ ħ/2: the product of the uncertainty in position (Δx) and the uncertainty in momentum (Δp) is greater than or equal to half the reduced Planck constant (a very small but importantly non-zero number).
What is less well-known is that the Uncertainty Principle applies to many other pairs of properties, perhaps the next most common pair of which is energy and time -- ΔEΔt ≥ ħ/2. This equation has far-reaching implications. Suppose we consider a small patch of empty space and contemplate the energy content there, if any. We know from the Uncertainty Principle that for any finite amount of time that you care to measure you will find your portion of 'empty' space has a decidedly non-zero energy (this energy is called the vacuum energy). This is not a question of the accuracy of your tools, it is a direct consequence of the wave-like nature of particles in quantum mechanics and is fundamentally built-in to the way the Universe works.
So our little region of space has a little bit of a buzz to it, so what? We now turn to the most famous equation in the world, Einstein's equation of mass-energy equivalence E = mc2. This suggests that from the vacuum energy matter can be created, although only in the form of virtual particles (vacuum fluctuations) with short lifespans as the Uncertainty Principle prohibits 'borrowing' energy from the vacuum indefinitely. (Sidenote: this is slightly misleading, as the relation E = mc2 only applies to real particles, with virtual particles lying slightly "off-shell" where E ≠ mc2. Even so, mass-energy equivalence remains valid and interestingly, the further off-shell a virtual particle is the shorter its lifetime, exactly as the Uncertainty Principle demands.) This means that out there in space, a sea of virtual particles are constantly flashing in and out of existence. This may sound like the ramblings of a madman, but so far as modern physics can tell it is an accepted fact.
Now, to give relevance to this slight digression, let's return to the question that sparked this blog post - why is there something rather than nothing? Well, what is nothing? A typical immediate response is to think of some small region of space deep in the void with nothing remotely nearby -- a classical vacuum. As I hope I have just demonstrated, however, this notion of nothingness is flawed as this region of space is not truly empty but is populated by virtual particles, fluctuations in the various quantum fields that permeate the universe. It seems we will have to reconsider what nothingness is, then.
Let us put aside quantum concerns for the moment. Even still the argument can be made that this does not constitute a reasonable view of nothingness. Wheeler's famous summary of general relativity (a purely classical theory) is: "Spacetime tells matter how to move; matter tells spacetime how to curve". We have forgotten that our region of empty space in a classical universe still contains, or rather consists of spacetime. In fact, we can do away with relativity altogether and still argue that we are envisioning a Universe endowed with space and time. Some may be reluctant to call these 'something', but since they have properies they are most definitely not nothing. Thus we must abandon our picture of a Universe with any notion of distance or duration, as nothingness precludes any such concept.
Now we are confronted with trying to conceive of a Universe which is literally nothing in the senses I have described above. There is so light, no matter, no particles of any description, not even space or time. Though it may seem unlikely, modern physics has the tools to deal with such a scenario, albeit in a somewhat imperfect way given our current knowledge of physics is not complete. What quantum field theory (perhaps the most accurate theory of physics ever discovered) suggests is that this nothingness is an unstable state and will inevitably and spontaneously turn into something. It seems that the way physics works just precludes nothingness from being a viable possibility. Problem solved, right?
Not quite. There is is one last resort for the hold-out, and that is to claim that nothingness is not only the absence of objects, fields, space, time and the rest, but also of physical law. While there is nothing wrong with this definition in principle, in practice it is nonsense. It only seems reasonable in my opinion that if someone is to establish their own definition of what constitutes 'nothingness' they should do so in an explicable way. This is simply not possible as it is so far outside of human experience that there is no reasonable way to explain it. Any analogy will fall short, any visualisation will falter; we had enough trouble trying to imagine a Universe with no notion of space or time!
What's more, how can we prove or disprove that such a nothingness can actually exist if we have deprived ourselves of all our tools for answering such a question? The typical recourse is to the supernatural, perhaps explaining that God somehow creates something from this absolute nothingness, which is established by hypothesis. But if this nothingness is so perfect, how can there be a God there at all? What meaning does the concept of God hold in such a scenario? Clearly He must have no physical properties as there are no physical laws, and cannot be within the Universe as it is by hypothesis nothing, so He must reside outside the nothingness, and yet be able to change it. It is at this point that I throw my hands up in the air and ask in exasperation what such a statement means, not in a deep or mystical sense but rather as a basic statement in the English language. It seems that this desperate endeavour has led us down a path which is, as I suggested earlier, nonsensical. We might as well discuss the colour of a red green, or the weight of an idea for all the progress such an approach can yield.
It may seem disingenuous to argue that we limit our definition of nothingness to what we, as flawed people, can comprehend, but in fact we have no other recourse than abandoning the question altogether. Given the curious nature of human beings, I doubt we will be able to withstand the temptation to revisit it, and so our hand is forced. It seems to me at least that we must restrict ourselves to discussing the question of why there is something rather than nothing in strictly physical terms, and that is why the question of why there is something rather than nothing strikes me as being especially peculiar in contrast to other important philosophical questions.
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