The Fabric of Reality: Towards a Theory of Everything (Penguin Science)

by David Deutsch

all evolution promotes the ‘good’

(i.e. the replication) of the best-replicating genes – hence the term ‘selfish gene

It is that the proponents of the prevailing theories – Popper, Turing, Everett, Dawkins and their supporters – have found themselves constantly on the defensive against obsolete theories.

That is of course true, but it is an answer in terms of prediction, and the problem is one of explanation. There is an explanatory gap.

The previous concept of a law of nature had been that of a rule stating what happens. An example is Johannes Kepler’s laws of planetary motion, which described how the planets move in elliptical orbits. This is to be contrasted with Newton’s laws, which are laws of physics in the modern sense. They make no mention of ellipses, though they reproduce (and correct) Kepler’s predictions under appropriate conditions.

what is on that cross-section. Spacetime does not change, therefore one cannot, within spacetime physics, conceive of causes, effects, the openness of the future or free will.

Freedom has nothing to do with randomness. We value our free will as the ability to express, in our actions, who we as individuals are. Who would value being random?

thanks to the multiverse character of quantum reality, free will and related concepts are now compatible with physics.)

this critic is forcing an analogy between, on the one hand, billions of years of planet-wide trial and error, and on the other hand an instantaneous accident of ‘happening to fall together

once we understand that the growth of human knowledge is a physical process, we see that it cannot be

illegitimate to try to explain how and why it occurs. Epistemology is a theory of (emergent) physics.

This often forces them to retreat into the core of their own strand. ‘Here I stand, I can do no other’ is their ultimate response, as they rely on the self-evident irrationality of abandoning the unrivalled fundamental theory of their own particular field.

explanation and understanding at the centre of human purposes.

Although history has no meaning, we can give it a meaning. Karl Popper

Tomasso Toffoli has remarked that ‘We never perform a computation ourselves, we just hitch a ride on the great Computation that is going on already.

We are not merely ‘chemical scum’, because (for instance) the gross behaviour of our planet, star and galaxy depend on an emergent but fundamental physical quantity: the knowledge in that scum.

In contrast, the explanatory structure that they jointly provide for the fabric of reality is not hierarchical: each of the four strands contains principles which are ‘emergent’ from the perspective of the other three, but nevertheless help to explain them.

we may ask what sort of role now seems natural for knowledge-creating beings such as ourselves in the unified fabric of reality. This question has been explored by the cosmologist Frank Tipler. His answer, the omega-point theory,

short, what justifies assuming that the full Turing principle holds at the end of the universe, is that any other assumption spoils good explanations of what is happening here and now.

Their thoughts will, like ours, be virtual-reality renderings performed by these computers. It is true that at the end of that final second the whole sophisticated mechanism will be destroyed.

But we know that the subjective

duration of a virtual-reality experience is determined not by the elapsed time, but by the computations that are performed in that time. In an infinite number of computational steps there is time for an infinite number of thoughts – plenty of time for the thinkers to place themselves into any virtual...

(There are no ‘natural’ constants in physics, goes the maxim, except zero, one and infinity.)

One of them is the epistemological principle that reality is comprehensible.

He would be mistaken, and badly so, for though we have the technology to build such structures, we have chosen not to.

unquestioned assumptions about human motivations have become obsolete after only a few centuries.

Indeed, no attempt to prophesy future large-scale developments in human (or superhuman) affairs can produce reliable results.

As Popper has pointed out, the future course of human affairs depends on the future growth of knowledge. And we cannot predict what specific knowledge will be created in the future – because if we could, we should by definition already possess that knowledge

However, none of these explanations fits the facts. On the one hand, we do not tend to explain inborn behaviour – say, epileptic fits – in terms of moral choices; we have a notion of voluntary and involuntary actions, and only the voluntary

Indeed, overriding both inborn and socially conditioned behaviours is itself a characteristic human behaviour.

This is a fatal flaw of this entire class of theories.

Could there be a gene for overriding genes when one feels like it?

Perhaps, but that still leaves the problem of how we choose ...

it too has a fatal flaw: we choose our preferences. In particular, we change our preferences,

the value of a design feature is understandable only in the context of a given purpose for the designed object. But we may find that it is possible to improve designs by incorporating a good aesthetic criterion into the design criteria. Such aesthetic criteria would be incalculable from the design criteria; one of their uses would be to improve the design criteria themselves.

role of intelligence in the multiverse. It is that intelligence is not only there to control physical events on the largest scale, it is also there to choose what will happen.