[Moonman62]

So we're confident that Inflation is reasonably close to the truth. From there, inferring the conditions close to the Big Bang is a matter of straightforward calculation. If those conditions had been ever so slightly different, the universe would look very different from the way it does now.

You said as an example that 50th decimal place values could be significant without Inflation. Above you seem to be saying that there is still some sensitivity to initial values even with inflation. Is that correct?

BTW, I really enjoy your Geek Alerts!

[Physicist]

Above you seem to be saying that there is still some sensitivity to initial values even with inflation. Is that correct?

No, the point is that Inflation pulls the density to the critical value, so that by the time the Inflationary epoch is over, the density is pegged to it.

Part of your confusion is caused by my sloppy wording, "close to the Big Bang". The end of the Inflationary epoch is much closer to the Big Bang than the energy explored by the LHC. The energy density at the time of inflation is comparable to the grand unification scale, way up there.