Natural State based living machines will be necessary for pure synthetic intelligence. Anything strictly machine based will have problems adapting to a persona continuance with living creatures (lessening of the death state).
As with the greatness of man, expansion of his semi-primitive heavy overhead electricity reliant machines can however create temporal synthetic intelligence (TSI) in a simple interlocking transformation valve using low radioactive DNA-based communication protocols.
Biophotonics will be key there.
As we develop living machines and apply soul machine inclusive designs (biological machines using virtual self images), TSI device specific science will begin to arise.
WTW