Well, scientists (physicists) usually tell, teach and train you in high school (via curriculum and laid out criteria) that matter can't be destroyed, so out of all religious theories it holds the most weight or "water", yet how that works with the spirit (/soul/conscious/mind) is unclear and likely doesn't follow any established dogma extracted from religious doctrines in the indian/south asian religions like hinduism or buddhism

You got reincarnation or cryonics/suspended animation until concepts like life extension or immortality become more studied in biomedicine or biotechnology, neuroscience and microbiology for humans, non-human mammals and birds