# David Deutsch - Quotes: 25 - Author page: https://www.leafyquotes.com/david-deutsch ## Books - [The Beginning of Infinity](https://www.leafyquotes.com/david-deutsch/the-beginning-of-infinity.md) — 7 quotes - [The Fabric of Reality](https://www.leafyquotes.com/david-deutsch/the-fabric-of-reality.md) — 18 quotes ## Recently added quotes > Experience is indeed essential to science, but its role is different from that supposed by empiricism. It is not the source from which theories are derived. Its main use is to choose between theories that have already been guessed. That is what ‘learning from experience’ is. [Quote page](https://www.leafyquotes.com/david-deutsch/the-beginning-of-infinity/experience-is-indeed.md) > Any theory about improvement raises the question: how is the knowledge of how to make that improvement created? Was it already present at the outset? The theory that it was is creationism. Did it ‘just happen’? The theory that it did is spontaneous generation. [Quote page](https://www.leafyquotes.com/david-deutsch/the-beginning-of-infinity/any-theory-about.md) > That progress is both possible and desirable is perhaps the quintessential idea of the Enlightenment. It motivates all traditions of criticism, as well as the principle of seeking good explanations. But it can be interpreted in two almost opposite ways, both of which, confusingly, are known as ‘perfectibility’. One is that humans, or human societies, are capable of attaining a state of supposed perfection – such as the Buddhist or Hindu ‘nirvana’, or various political utopias. The other is that every attainable state can be indefinitely improved. Fallibilism rules out that first position in favour of the second. [Quote page](https://www.leafyquotes.com/david-deutsch/the-beginning-of-infinity/that-progress-is-both.md) > The misconception that knowledge needs authority to be genuine or reliable dates back to antiquity, and it still prevails. To this day, most courses in the philosophy of knowledge teach that knowledge is some form of justified, true belief, where ‘justified’ means designated as true (or at least ‘probable’) by reference to some authoritative source or touchstone of knowledge. [Quote page](https://www.leafyquotes.com/david-deutsch/the-beginning-of-infinity/the-misconception-that.md) > Could it be that the moral imperative not to destroy the means of correcting mistakes is the only moral imperative? That all other moral truths follow from it? [Quote page](https://www.leafyquotes.com/david-deutsch/the-beginning-of-infinity/could-it-be-that.md) > If something is permitted by the laws of physics, then the only thing that can prevent it from being technologically possible is not knowing how. [Quote page](https://www.leafyquotes.com/david-deutsch/the-beginning-of-infinity/if-something-is-permitted.md) > Let me define that [wealth] in a non-parochial way as the repertoire of physical transformations that they would be capable of causing. [Quote page](https://www.leafyquotes.com/david-deutsch/the-beginning-of-infinity/let-me-define.md) > The next chapter is likely to provoke many mathematicians. This can't be helped. Mathematics is not what they think it is. [Quote page](https://www.leafyquotes.com/david-deutsch/the-fabric-of-reality/the-next-chapter.md) > The quantum theory of parallel universes is not the problem, it is the solution. It is not some troublesome, optional interpretation emerging from arcane theoretical considerations. It is the explanation—the only one that is tenable—of a remarkable and counter-intuitive reality. [Quote page](https://www.leafyquotes.com/david-deutsch/the-fabric-of-reality/the-quantum-theory.md) > Reality contains not only evidence, but also the means (such as our minds, and our artefacts) of understanding it. There are mathematical symbols in physical reality. The fact that it is we who put them there does not make them any less physical. [Quote page](https://www.leafyquotes.com/david-deutsch/the-fabric-of-reality/reality-contains-not.md) > Necessary truth is merely the subject-matter of mathematics, not the reward we get for doing mathematics. The object of mathematics is not, and cannot be, mathematical certainty. It is not even mathematical truth, certain or otherwise. It is, and must be, mathematical explanation. [Quote page](https://www.leafyquotes.com/david-deutsch/the-fabric-of-reality/necessary-truth-is-merely.md) > It is possible to build a virtual-reality generator whose repertoire includes every possible environment. [Quote page](https://www.leafyquotes.com/david-deutsch/the-fabric-of-reality/it-is-possible.md)