I am currently reading Max Tegmark's book "Our Mathematical Universe" in which he argues for an infinite number of parallel multiverses. It seems to me that the basis for his postulating the multiverses is that "eternal inflation" occurs and continues to occur in space regions even after a particular space region (like ours) undergoes a big bang. It also seems to me that the infinity of multiverses and all its dramatic consequences such as "everything that can occur will occur" and do so an infinite number of times is already inherent and simply a consequence of the concept of "eternal" expansion. Therefore before I suspend my belief in the finite and accept the seeming bizarre claims of the infinite (e'.g. that there are multiple copies of nearly me in the spectrum of multiverses) I'd like some help in understanding the rationale of "eternal" inflation. Thanks kindly.