Reply #6: New souls come into existence

[SheilaT]

constantly.

I can't figure out why a limited number of souls seems to be a valid counter-proof to reincarnation, and yet to any other theological system.

Here are two phenomenal books to read:
Journey of Souls and Destiny of Souls both by Michael Newton. He's a hypnotherapist who stumbled across past lives somewhat accidentally in his practice, and wound up asking a lot of questions about life between lives. Among the things discussed is how souls are born from the "over-soul".