Castrup distinguishes between hardware and software by arguing that hardware is what actually exists (physical states of matter and energy), while software is pure abstraction—a pattern imposed upon and interpreted from hardware; therefore, to understand what a computer truly is and what consciousness in systems looks like requires studying hardware, not software abstractions.

Despite Castrup coming from computer engineering (bottom-up systems thinking) and Levin coming from biology (top-down organism thinking), they have adopted each other's traditional approaches—a curious philosophical reversal suggesting that disciplinary training sometimes inverts rather than confirms naive intuitions.