Cryonics has been based on materialist reductionist idea expressed by Drexler: Memory and Personality are embedded in preservable brain structure. (Engines of Creation, 1984). Lately, however, after reading Doug Matzke, I'm leaning more toward a quantum-reality or "deep-reality" that provides the base-foundation for the expression of the matter-energy-field we experience as materialists believe it to be. I found another "soul" on reddit:cryonics who might believe something similar as they posted an IQ graphic describing the percentiles of cryonicists IQ's who understand that notion here...
https://www.reddit.com/r/cryonics/comments/xs25pc/connectomics_is_virgin_neuroscience_the_quantum/