Science

One's beliefs are convenient when he can make successful predictions, for example about the results of his actions.

We can always doubt that our convenient beliefs are true. It's not worth worrying about this doubt, because it doesn't recommend any particular course of action.

Acquisition of convenient belief

One has beliefs about reality and one's relation to it, with an idea of how different actions will affect it. Everyone, including new born babies and animals, has beliefs along these lines. Such beliefs may be conscious, such as a physicist's understanding of string theory; or unconscious, such as a monkey's (or human's) ability and tendency to stick its hairs on end when frightened. The unconscious beliefs are referred to as beliefs because it is convenient to talk about them this way in modeling behaviour, not because these beliefs are perceived by the conscious mind of the actor.

All one can do in finding a method for acquiring convenient belief is to try to describe past actions, by him and by others. He will see that they come from a simplistic decision-making process, causing his action at any one instant. He can consider how things might have turned out had he acted differently. He can then develop ideas for how he should behave differently. The process will relate to these ideas as well as other feelings. He keeps these ideas with him and they modify his actions. This process will repeat, transfinitely.

The actor perceives the world to be largely predictable by his beliefs. The world develops along deterministic lines. This means it can be described according to some mathematical algorithm, with physical and subjective slotting into the skeleton.

Superficial theories still have predictive power, as the systems they describe emerge from whatever deep foundations physics has.

I will give methods of determining convenient truth that I perceive to be sensible, acquired in the foregoing manner:

  • A system must show itself to be reliable. There should be no counter-examples.
  • A system must attempt to be a single cohesive whole, lacking arbitrary facts and special cases existing in isolation from the main body of belief. The example has been given of a turkey who deduces that its life is safe because it constantly experiences that it is not killed. Then it is killed and cooked for Christmas dinner. The turkey was not capable of reasoning about a higher order of things. It only had a collection of observations and didn't link them together in a higher theory. It didn't ask, Why is it that I remain alive? Why am I kept on this farm? There may be beliefs we take for granted, but we should be open to every idea and possibility that we can lay our hands upon about the way that the world may work.

Probability

These beliefs will include the concept of 'probability,' which needs a careful definition. Probability describes a class of binary experiments. It is a number between 0 and 1 (for our purposes it doesn't matter whether we are using the reals or the rationals or whatever) that is the long-term proportion of any sequence of 'independent' members of this class which have a positive result. This concept is used in modeling behaviour. What action will result from probabilistic sentiment will differ from actor to actor.

'Independent' should be taken to mean that the event is primary. Probabilities of derived events can be calculated, but in one's understanding the source of the uncertainty comes from the independent events. Given a collection of correlated random variables, it should be possible (but I'm not sure) to find a collection of independent random variables which give the same information. Coin tosses are viewed as independent. A deeper understanding of physics might say they were dependent, but that isn't possible or practical.

Probabilities occur as fundamental sentiment and as acquired theory. A trader in financial derivatives may be using a complicated probabilistic model to inform his actions. He has an expectation that his model will work. The probabilistic outlooks that his sentiment can correspond to will be a lot simpler than his models. There is a new entity in his mind, which the hazy probabilistic sentiment will relate to instead.

Events and statements cannot be assigned probabilities. Using Bayes's theorem, we can derive a posterior distribution from a prior one, but there's no obvious way of getting an initial distribution. One way would be to list n cases and assign each a probability of 1/n. However, this depends on how you listed the cases, as any one case could be increased in probability by being divided into sub-cases.

Probabilities should be assigned to events based on sentiment, and then developed as in the previous section.

Physics

Physics is like economics. I find physics easier to understand, because it more explicitly explains what the structure of the theory is.

It seems that a physical theory is a mathematical object. For example, in Newtonian mechanics, the object is a map from R^3 (Euclidean space) x R (Euclidean time) to the Cartesian product of sets of possible values of certain properties like mass, velocity and charge. This is a valid theory if it satisfies certain differential equations.

Which mathematical object represents the/our universe, and why that particular one?

Quantum Mechanics

The universe is a wave function. For a single observer, observations collapse the wave function. For that observer, considering other observers' effect on the wave function leads to an interesting choice. Either option is weird.

  • Choice 1 - The other observers can collapse the wave function too. So in this case, consciousness is special. Conscious observers have an effect on the universe that unconscious matter doesn't.
  • Choice 2 - When other observers make an observation, to the original observer they enter the state of superposition the system they were observing was in. Only the first observer can collapse the wave function. In this case, We all inhabit our own universes, each with their own wave functions.

Another choice would be that all matter is conscious and it constantly observes itself, so conscious isn't special. I don't know if that would work though. Wouldn't that just be traditional physics?

There aren't many experiments you can do to know whether parallel universes exist. I'm interested in the idea of quantum_immortality. You couldn't test this without risking your life, but I think it would still be worthwhile to try it out on an animal. You could have Schrödinger's cat with the option of pushing a button, which will either kill the cat, or give it milk, depending on some random quantum process. If quantum immortality is true, then the cat would learn that pressing the button would give it milk. At least then, somewhere in the multiverse, there'd be a conscious being whose actions relied on the principle of the existence of parallel universes. I think a few dead cats would be worth this possibility. Maybe in time these cats would evolve into pan-dimensional beings capable of traveling across time and probability in ways we can't comprehend.

The relation of physical theories to conscious experience

Theories of physics should be augmented with a description of how they are experienced. Quantum mechanics, and general relativity both tend to Newtonian physics (or even Aristotelian physics, maybe) in ordinary, everyday experience, and we make a good start on this augmentation in describing how classical, more intuitive physics might be experienced by human beings.

  • The Euclidean 3-dimensional space that a human being is surrounded in, with a special direction of gravity, is experienced as a ‘feeling of being in oriented 3-dimensional space,’ which mainly includes elements of vision, balance, and motor control (knowing where your limbs are in space), with some elements of hearing (one can tell in which direction a sound is coming from) (There is a complication in that there are "local" aspects of three-dimensional shape, which don't have to be situated at an exact position within a three-dimensional space. This is demonstrated by impossible shapes, like the tribar. )
  • The amount of light which is shooting around and the colours in it are experienced in vision
  • The temperature of the surrounding air and objects one is touching and changes thereof are experienced as a feeling of temperature and changes thereof
  • Physical reaction forces from solid objects are experienced through touch and strain in muscles

We won't be able to describe all aspects of experience because many of them, such as having an unsettled stomach, or having a thought, are heavily reliant on the composition of the body and brain, and in physics we tend to consider more general mechanisms that apply equally well outside the body.

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