# The Fabric of Reality ## Metadata * Author: [David Deutsch](https://www.amazon.comundefined) * ASIN: B005KGJX8E * Reference: https://www.amazon.com/dp/B005KGJX8E * [Kindle link](kindle://book?action=open&asin=B005KGJX8E) ## Highlights understanding does not depend on knowing a lot of facts as such, but on having the right concepts, explanations and theories. — location: [92](kindle://book?action=open&asin=B005KGJX8E&location=92) ^ref-58140 --- For a theory to predict something ‘in principle’ means that the predictions follow logically from the theory, even if in practice the amount of computation that would be needed to generate some of the predictions is too large to be technologically feasible, or even too large for it to be physically possible for us to carry it out in the universe as we find it. — location: [96](kindle://book?action=open&asin=B005KGJX8E&location=96) ^ref-33927 --- Facts cannot be understood just by being summarized in a formula, any more than by being listed on paper or committed to memory. They can be understood only by being explained. Fortunately, our best theories embody deep explanations as well as accurate predictions. — location: [106](kindle://book?action=open&asin=B005KGJX8E&location=106) ^ref-25172 --- Scientific theories explain the objects and phenomena of our experience in terms of an underlying reality which we do not experience directly. But the ability of a theory to explain what we experience is not its most valuable attribute. Its most valuable attribute is that it explains the fabric of reality itself. — location: [113](kindle://book?action=open&asin=B005KGJX8E&location=113) ^ref-6897 --- They consider that any consistent explanation that a theory may give for its predictions is as good as any other – or as good as no explanation at all – so long as the predictions are true. This view is called instrumentalism (because it says that a theory is no more than an ‘instrument’ for making predictions). — location: [118](kindle://book?action=open&asin=B005KGJX8E&location=118) ^ref-598 --- But how exactly would that help us to build one, or to build another oracle of the same kind - or even a better mousetrap? The oracle only predicts the outcomes of experiments. Therefore, in order to use it at all we must first know what experiments to ask it about. If we gave it the design of a spaceship, and the details of a proposed test flight, it could tell us how the spaceship would perform on such a flight. But it could not design the spaceship for us in the — location: [135](kindle://book?action=open&asin=B005KGJX8E&location=135) ^ref-47520 --- first place. And even if it predicted that the spaceship we had designed would explode on take-off, it could not tell us how to prevent such an explosion. That would still be for us to work out. And before we could work it out, before we could even begin to improve the design in any way, we should have to understand, among other things, how the spaceship was supposed to work. Only then would we have any chance of discovering what might cause an explosion on take-off. — location: [138](kindle://book?action=open&asin=B005KGJX8E&location=138) ^ref-32789 --- Prediction – even perfect, universal prediction – is simply no substitute for explanation. — location: [142](kindle://book?action=open&asin=B005KGJX8E&location=142) ^ref-30808 --- there already is one such oracle out there, namely the physical world. It tells us the result of any possible experiment if we ask it in the right language (i.e. if we do the experiment), though in some cases it is impractical for us to ‘enter a description of the experiment’ in the required form (i.e. to build and operate the apparatus). But it provides no explanations. — location: [155](kindle://book?action=open&asin=B005KGJX8E&location=155) ^ref-54576 --- An extreme form of instrumentalism, called positivism (or logical positivism), holds that all statements other than those describing or predicting observations — location: [167](kindle://book?action=open&asin=B005KGJX8E&location=167) ^ref-17012 --- are not only superfluous but meaningless. — location: [169](kindle://book?action=open&asin=B005KGJX8E&location=169) ^ref-43222 --- To say that prediction is the purpose of a scientific theory is to confuse means with ends. It is like saying that the purpose of a spaceship is to burn fuel. In fact, burning fuel is only one of many things a spaceship has to do to accomplish its real purpose, which is to transport its payload from one point in space to another. Passing experimental tests is only one of many things a theory has to do to achieve the real purpose of science, which is to explain the world. — location: [183](kindle://book?action=open&asin=B005KGJX8E&location=183) ^ref-17950 --- might seem that every time a new explanation or technique is discovered that is relevant to a given subject, another theory must be added to the list that anyone wishing to understand that subject must learn; and that when the number of such theories in any one subject becomes too great, specializations develop. — location: [200](kindle://book?action=open&asin=B005KGJX8E&location=200) ^ref-6672 --- More indirectly, better explanations in any subject tend to improve the techniques, concepts and language with which we are trying to understand other subjects, and so our knowledge as a whole, while increasing, can become structurally more amenable to being understood. — location: [216](kindle://book?action=open&asin=B005KGJX8E&location=216) ^ref-58032 --- We understand the fabric of reality only by understanding theories that explain it. And since they explain more than we are immediately aware of, we can understand more than we are immediately aware that we understand. — location: [261](kindle://book?action=open&asin=B005KGJX8E&location=261) ^ref-57780 --- Just as it is hard to define what an explanation is, it is hard to define when a subsidiary explanation should count as an independent component of what is understood, and when it should be considered as being subsumed in the deeper theory. — location: [270](kindle://book?action=open&asin=B005KGJX8E&location=270) ^ref-42756 --- modern theories are fewer, more general and deeper. — location: [298](kindle://book?action=open&asin=B005KGJX8E&location=298) ^ref-21694 --- In the past, some great advances in understanding came about through great unifications. Others came through structural changes in the way we were understanding a particular subject – as when we ceased to think of the Earth as being the centre of the universe. After the first Theory of Everything, there will be no more great unifications. All subsequent great discoveries will take the form of changes in the way we understand the world as a whole: shifts in our world-view. The attainment of a Theory of Everything will be the last great unification, and at the same time it will be the first across-the-board shift to a new world-view. I believe that such a unification and shift are now under way. — location: [351](kindle://book?action=open&asin=B005KGJX8E&location=351) ^ref-30913 --- another mistaken view of the nature of science, held disapprovingly by many critics of science and (alas) approvingly by many scientists, namely that science is essentially reductionist. That is to say, science allegedly explains things reductively – by analysing them into components. — location: [369](kindle://book?action=open&asin=B005KGJX8E&location=369) ^ref-21039 --- High-level phenomena about which there are comprehensible facts that are not simply deducible from lower-level theories are called emergent phenomena. — location: [393](kindle://book?action=open&asin=B005KGJX8E&location=393) ^ref-18802 --- The purpose of high-level sciences is to enable us to understand emergent phenomena, of which the most important are, as we shall see, life, thought and computation. — location: [396](kindle://book?action=open&asin=B005KGJX8E&location=396) ^ref-25207 ---