I'm asking many questions on inflation, I hope this is the last one... If inflation is correct, our observable Universe would have been a tiny homogeneous patch before inflation started (if it started at all). The length of that initial patch is estimated to be of the order of 1 Hubble length at the time before inflation (see for instance Guth's notes, and 1992 paper, or this video lecture). This turns out to be something like 10-26 cm or 10-28 cm, that kind of crazy size, depending on the sources. Why is the initial patch length estimated to be of the order of 1 Hubble length at that time ? I understand that a patch of that size is causally connected, providing homogeneity. But when we talk of the horizon distance problem of the standard Big Bang, we use the particle horizon as the criteria for causal connection, not the Hubble distance.