The Fabric of Reality, According to David Deutsch

In his book "The Fabric of Reality", David Deutsch identifies four fundamental aspects of knowledge underlie the nature of reality. These are:

1. Quantum Physics: This aspect deals with the fundamental nature of matter and energy, and how they behave at the atomic and subatomic level.
2. Epistemology: This strand of knowledge deals with the theory of knowledge itself, including the methods of acquiring and validating knowledge, and the relationship between knowledge and reality. More colloquially, this is known as “How do we know what we know”.
3. Evolutionary Theory: This refers to the processes of natural selection and how they shape the development of life on earth.
4. Theory of Computation: This focuses on the nature and limitations of computation and how it can be used to model and understand complex systems, including the universe itself.

According to Deutsch, these four strands of knowledge are all interconnected and can be used to build a unified understanding of reality.