There are several threads in the forum on this subject, but I see no satisfying reason that we need inflation. The explanation I typically see is that assuming homogeneity of early universe as an initial condition presents a "fine tuning" problem. Why so much weight on that problem? One could as well argue that the approach to infinite density of the entire universe at a precise finite time in the past is also a fine tuning problem. So I'm wondering if there are other issues that force us toward inflation. E.g. is it possible that, even if the start was uniform, this uniformity would quickly deteriorate (perhaps due to random quantum fluctuations or some sort of early clumping on small scales)? I am familiar with the argument that no matter how close you get to the BB event, there are neighboring sections of the universe that are not in causal contact (because the expansion is too fast). But so what? The beginning is beyond our ken so why not just assume uniformity, if that fixes the problem? Even if we assume initial non-uniformity, how can we possibly know the magnitude of this non-uniformity? Nevertheless, theorists seem to be estimating how many e-folds of inflation are needed to reach the current CMB uniformity. How can they do that with unknown initial conditions? Inflation theory appears to be very important to cosmologist. All sorts of mechanisms have been proposed. There is a lot of debate about inflation (not so much about whether it occurred, but how it occurred). Papers concerning inflation are published daily. Yet it's not a very appealing theory because it forces us to give up a simple account of the BB and look for a much more complex account involving unknown physics. This leads me to believe that there is indeed a real need for inflation beyond avoidance of special initial conditions. So my question is what is this need, if there is one?