Deutsch's four strands (quantum physics, evolution, theory of computation, and epistemology) each, on its own, feels cold and incomplete. But together, they form a coherent picture of reality, as each strand fills the gaps of the others.
Book: The Fabric of Reality
In Four-strand Theory of Everything, we introduced how David Deutsch proposes reality is a fabric woven from four strands: quantum physics, evolution, theory of computation, and Popperian epistemology.
However, Deutsch acknowledged that each strand looks bleak and incomplete in isolation.
- Quantum theory provides accurate numbers in theory but seems random and feels like chaos.
- Evolution explains adaptation but looks purposeless as life is just blind selection.
- Computation defines limits but appears as abstract mathematics detached from the material world.
- Popper shows how knowledge grows through error correction but never grants certainty.
In Deutsch's view, each strand fills one another's gaps.
For example, quantum physics plus computation gives quantum computing. Deutsch argues that this computing is a physical process carried out across many branches of reality, and the final result comes from their interference.
This connection fills the explanatory gap: computation becomes a physical process embedded in the multiverse, and quantum mechanics is no longer a random mystery but a structured information flow.
Another example, evolution plus epistemology reframes ideas as populations. Knowledge growth itself can be seen as an evolutionary process. Just as species survive by adapting, ideas survive by resisting criticism.
This fills another gap: epistemology gains a biological grounding, while evolution is revealed as a general process that applies not just to organisms but also to culture and science.
Alone, each strand feels thin and leaves gaps. Together they form a single coherent picture of reality.