Given the incredible improbability ( a “0.00000000001% difference in either direction would render the Universe completely inhospitable to any life”) that the density and expansion rate of the universe would be so finely balanced, it leads one to think that they are probably related (that the rate of expansion is determined by the density of the universe, or vice versa).

This is not to say that life is pre-ordained — it can be an incidental consequence of this stability — 0nly that the ‘stability’ is inherent to the explosion. But I don’t suppose anyone has yet found a reason why expansion and density should constrain each other?