Expanding on the work of Karl Popper, The Beginning of Infinity by David Deutsch represents what may be considered the definitive work of the philosophy of science for the twenty-first century. What follows is a brief outline of that philosophy.
In general, Deutsch is making the claim that knowledge and biological adaptation share a similar history of development (although they are much different in other important ways). In terms of biological adaptation, variation in genes results in different biological forms which are then selected via the process of natural selection. The information needed to assemble biological forms is contained within the genes.
Likewise, knowledge evolves by variation, in the form of conjectures or explanations, about some phenomenon, which are then selected via traditions of criticism and experimentation.
And so the process of variation and selection results in the evolution of both biological forms and knowledge. However, unlike biological evolution, knowledge is expressed in the form of explanations that have potentially infinite reach. For example, the theory of gravity is an explanation that can provide information about the farthest reaches of the universe despite the fact that we’ve never travelled there.
Variation, in the form of conjectures, generates different explanations that can then be criticized and tested. But it’s only through a tradition of criticism and testing that knowledge can evolve to become more refined. And this fact explains the explosion of knowledge we’ve witness over the last 400 or so years since the scientific revolution and the Enlightenment (which are essentially systems and traditions of criticism).
The Enlightenment, which included the scientific revolution, was characterized by a rejection of authority, dogma, and any system of belief that insulated itself against criticism and change. This insulation against criticism and change characterizes all failed societies and systems of thought.
The new scientific sensibility, in contrast, took nothing for granted, and even treated its own theories as provisional, or subject to change in the face of new evidence or better explanatory theories.
In this way, all knowledge is treated as conjecture, subject to the selection process of criticism and testing, allowing knowledge to grow and expand infinitely.
In the process, we’ve come to discover the criteria for good explanations. The nature of our reason is that we can never know anything with complete certainty; our knowledge, as a result, must be probabilistic. But within that constraint we can develop explanations that are increasingly accurate and precise.
Accuracy and precision are important standards in our evaluation of explanations, the very standards that are absent in bad explanations. For example, using creationism to explain biological adaptation is a bad explanation because to say that “God designed life” is to not really explain anything at all. It says nothing of the the nature of God, how God came into existence itself, and why specific adaptations were designed to the exclusion of others.
More importantly, in bad explanations, the details are easy to vary. The creationist, faced with any specific example of poor design in our own biology, can simply make up an explanation for its existence or make the claim that God is infinitely wiser than us, so that there must be a reason.
This is the mark of a bad explanation: one that can never be wrong regardless of any new thought, criticism, discovery, evidence, or testing procedure. Biological evolution, in contrast, represents a good explanation because it not only fits the evidence but the details are hard to vary. This means that evolution could be disproven by finding a fossil out of place, or by showing a biological adaptation that spontaneously generated without ancestral precursors.
Within this entire epistemology is the concept of fallibilism, the importance of theory, and the importance of a system of criticism.
Fallibilism is the principle that all of our theories, both scientific and based on common sense, are subject to varying degrees of doubt and so can never be conclusively proven. Even formal systems such as mathematics and logic cannot prove their own axioms from within their own systems and must rely on outside sources, ad infinitum.
Every argument includes premises in support of a conclusion, but the premises themselves are left unargued. If those premises are then supported with further argument, then the premises for that argument are left unsupported.
This results in an infinite regress and a permanent state of doubt, and the deeper our explanations go, the more questions arise. This is why problems are inevitable. But problems are also soluble, even if our knowledge is only probable. We can solve problems as they arise, but—and here’s another key point—we can’t know which problems are soluble before we solve them.
That’s why premature cognitive closure is the antithesis to Deutsch’s theory; the resignation of problems as unsolvable, or of existing belief as certain, prevents the possibility of knowledge growth. Perhaps some problems are unsolvable, but since we don’t know which will be solved ahead of time, we must of practical necessity assume that they are.
This will lead to the development of explanatory theories (variation), which can then be criticized and tested (selection). The theories that withstand the testing become the currently best explanations. And so a kind of evolutionary process is occurring within the mind.
Theory and abstract explanations always proceed testing, as gene variation always precedes natural selection. That is because experimental data always needs to filtered and assessed according to some theory. The idea of empiricism, that observational data just spontaneously assembles itself into theory and knowledge, is false. Newton’s laws of universal motion, for example, cannot be derived simply from observing objects in motion. It is an explanatory theory that can be tested, but must be a theory first.
Overall, Deutsch’s philosophy replaces the search for certainty with the search for better explanations and unbounded growth in knowledge, which is the core philosophy that helped humankind transition out of the dark ages.