II : The Big Questions Both Books Answer
Reality, Knowledge, Progress, and the Societies That Enable Them
“Civilizations are built on the questions they dare to ask, and the courage to improve the answers.”
If you could only ask four questions about existence, and your civilization’s survival depended on the answers, what would they be?
For David Deutsch, these are not just philosophical curiosities; they are the pillars for how a civilization survives, grows, and shapes its own future.
His two books, The Fabric of Reality (1997) and The Beginning of Infinity (2011), are attempts to answer these four questions in a way that works now and remains improvable for as long as humanity exists.
1. What is reality?
Reality is everything that exists, whether we can see it directly or not.
For Deutsch, the most accurate current picture of reality comes from combining four powerful theories:
Quantum Theory: This is the branch of physics that explains the behavior of matter and energy at the smallest scales. It says reality is a multiverse, meaning that many possible versions of events exist and evolve simultaneously, even if we only experience one.
Example: In quantum physics, a particle like an electron can be in more than one place at once until it’s measured.Computation Theory: This is the science of what can be calculated or simulated. It’s the foundation of computer science, but Deutsch applies it to the universe itself, the idea that the universe processes information the way a computer does.
Example: Weather models use computation to predict storms; the universe itself “computes” how particles move.Theory of Evolution: Usually applied to biology, but Deutsch extends it to ideas and culture. Just as species evolve by variation and selection, so do technologies, languages, and moral systems.
Epistemology: This is the study of knowledge: how we know what we know. Deutsch focuses on the method of conjecture and criticism, guessing bold ideas and then trying hard to prove them wrong.
Real-world anchor: Your GPS works because it uses relativity to account for time differences in satellites and quantum mechanics for extremely accurate clocks. This is physics, not magic.
2. What is knowledge?
Most people think of knowledge as “facts” or “true beliefs.” Deutsch defines it more precisely: knowledge is information that has causal power; it can bring about change in the world.
It must be physically embodied in something: your brain, a book, a computer chip.
It is created through conjecture (bold guesses) and criticism (testing and trying to refute those guesses).
All knowledge is fallible, meaning it can be wrong, but some knowledge is better because it survives repeated attempts to disprove it.
Good knowledge is explanatory, not just predictive. It tells us why things happen, not just what will happen.
Example: The belief that “mosquitoes spread malaria” is knowledge because it can guide effective action (mosquito control), not just because it’s true. It’s embedded in physical systems like medical textbooks, lab experiments, and prevention programs.
3. Can we achieve infinite progress?
Deutsch’s answer: Yes, in principle.
Problems are inevitable because solving one often reveals new ones.
But any problem that doesn’t break the laws of physics can be solved, given the right knowledge.
Progress is open-ended: there is no final frontier of understanding, only temporary limits based on what we know now.
Example: Flight was “impossible” until we learned enough physics and engineering to build airplanes. Then space travel was “impossible” until we learned enough to make rockets. Each solved problem unlocks the next level of possibility.
4. How should we build societies that foster it?
Progress depends on more than science and technology; it needs the right kind of social environment.
Open societies, where people can speak freely, criticize ideas (even sacred ones), and try new things without permission, are the best engines for creating new knowledge.
These societies are also better at fixing their own mistakes, because criticism is allowed and encouraged.
Moral knowledge evolves the same way scientific knowledge does: through debate, testing, and improvement over time.
Example: The internet allows a scientist in Kenya to share data with a researcher in Brazil instantly. That openness can speed up solutions — as seen with COVID-19 vaccine development.
Why These Questions Matter Now
If we misunderstand reality, we act on false maps and build fragile systems
If we misunderstand knowledge, we can’t tell truth from propaganda
If we stop believing progress is possible, we accept decline as inevitable
If we build closed societies, we suffocate the very process that makes progress possible
These four questions are not just theoretical; they’re the coordinates for navigating a world that’s changing faster than we can track.
Where We Go Next
The Fabric of Reality and The Beginning of Infinity are more than just books — they’re two halves of a single mental operating system.
The first gives us the map of reality: a four-strand weave of quantum theory, computation, evolution, and epistemology.
The second gives us the engine: an optimistic, open-ended model of progress built on the power of good explanations.
Together, they argue that reality is knowable, knowledge is improvable, and progress is potentially infinite, if we choose to keep creating, testing, and refining our ideas.
But before we can use this blueprint to build the future, we need to understand its foundation. That means starting with the first strand: Quantum Theory and why Deutsch believes it reveals not just strange particles, but an entire multiverse.
In the next section, we’ll explore The Fabric of Reality’s Four Strands of Reality — the interconnected theories that form Deutsch’s answer to “What is reality?” and “What is knowledge?”
Glossary
(Quick reference for key terms used in this chapter)
Quantum Theory: Physics that explains the behavior of matter and energy at the smallest scales, where probability rules instead of certainty
Multiverse: The idea that many possible versions of reality exist at once, as predicted by quantum theory
Computation Theory: The study of what can be calculated, and how systems (like computers or the universe) process information
Theory of Evolution: The explanation of how living things change over generations through variation and natural selection, extended here to ideas and culture
Epistemology: The philosophy of knowledge: how we form ideas, test them, and decide which ones to keep
Conjecture and Criticism: A method of creating knowledge: make bold guesses and try to prove them wrong
Fallible/Fallibilism: The view that all knowledge can be wrong, and the way to improve it is through continuous testing and correction
Open Society: A society that protects free speech, debate, and criticism, enabling faster problem-solving and moral progress
Error Correction: The process of finding and fixing mistakes in ideas, systems, or understanding, is a central driver of progress