madmax2976

Consider:

1. The universe is all that there is and it operates according to physical laws.

2. The human brain operates according to physical laws as well, since it exists in the universe.

3. Since we can use the laws of the universe to predict events, reactions, etc., would it not be possible, at least in principle, to predict the activity of the human mind as well?

4. I consider it understood for this question that we may be prevented from doing the prediction due to lack of precision or ability in our measuring devices (chaos) and due the vast myriad of factors involved etc., but I'm concentrating in the "in principle" part here. Consider this question ontologically.

malpensante

yes, it is in pple possible, i haven't found an apriori refutation to this possibility. the only one may be that the intelligence required to completely predict a human mind may exceed a human mind, but maybe not a humanoid mind from some genetically engineered thinker or an artificial intelligence.

tronvillain

Even if you ignore all difficulties in measurement and calculation, you are still left with the possibility of random elements which might make predictions probabilistic rather than absolute.

madmax2976

"Random elements" such as?

excreationist

madmax2976:
Well what about the decay of radioactive isotopes...? e.g. within its half-life, about half of the atoms decay. I wonder if it is possible to predict exactly when each individual atom will decay. Maybe quantum entanglement is involved, so that it is deterministic.
The brain would be affected by apparent chaos of radioactive decay.

Synaesthesia

In principle it's certainly possible to anticipate human behavior. In fact, we do it all the time and to a degree of accuracy that will never, ever be matched by the tracking the molecular machinery of the mind.

Even forgetting the random elements, the difficulties in getting detailed prediction of the brain’s workings on a molecular level are insurmountable. To get an idea of how insurmountable, remember that to do a single protein folding calculation, the fastest computer in the world could take about 100 years. (at about a million dollars per year in operating costs with a 250 million dollar machine.)

Each living, pulsing neuron contains billions of proteins. There are about 100,000,000,000 neurons and trillions. of synapses connecting them together. With the behavior of each individual detail of the brain being so difficult to predict, the combinatorial explosion of the total quickly puts atomic-level prediction out of reach to all but gods.

excreationist

Not only would you have a simulate every neuron in the brain, you'd also need to duplicate the workings of the universe, since with quantum entanglement, any particle in the universe may affect any other one, no matter how distant.
Otherwise you'd just be simulating a brain that is completely cut off from the universe, which isn't very useful since even when we are asleep, our brain is being affected by outside forces. (e.g. even without quantum entanglement, the intake of air particles is pretty chaotic, and the chaotic changes in oxygen levels in the blood would affect neurons).

madmax2976

I understand the difficulty, even the unlikelihood of human beings ever being able to completely predict human actions/activities. However, as I said, I am concentrating on the onotological aspects of this rather than the practical aspects.

I'll try to flesh this out more clearly.

1. The universe is deterministic and operates according to physical laws.

2. This makes events/reactions within the universe predictable.

3. The human brain operates according to physical laws making its events/reactions predictable, in principle.

The end result of this of course would be that humans really don't make choices. We are constrained to do what we do because of universal laws.

bd-from-kg

madmax2976:

Almost everything you say here is (IMHO) wrong.

According to the standard interpretation of quantum mechanics, the universe operates according to physical laws which involve an element of intrinsic randomness. If this is correct, the universe is not deterministic.

Not so. According to chaos theory, even if the universe is deterministic future events are not predictable, even in principle. More precisely, for any given degree of precision to which you choose to do your calculations, round off error (or errors in the values of the original parameter that you feed into the calculations) will cause the results to be significantly in error – to the extent that you will, for example, predict a major war that does not occur or vice-versa. And this point will come surprisingly soon. For example, if you do your calculations to 10,000 decimal digits, your results will be seriously in error (war vs. no war) in a few years at most.

Even ignoring the earlier errors, this conclusion is false. If I eat a candy bar because I want to eat a candy bar, it is an abuse of language to say that I am “constrained” to do it. I would be “constrained” to do it only if I were forced to do it against my will.

To illustrate this vital point, suppose that Smith, Jones, and Phillips each finds a wallet containing a large sum of money as well as the owner’s name, address, and telephone number. Now let’s look at the results:

1. Smith is a man of rock-solid integrity and honesty. He returns the wallet to its rightful owner without a second thought.

Did Smith make a choice? Of course. He could have kept the money, but chose not to because he is a man of good character.

2. Jones is strictly a look-out-for-number-one type. He always does what he perceives to be in his best interest. Since there seems to be a vanishingly small likelihood of being found out, he keeps the money.

Did Jones make a choice? Of course. He could have returned the money, but chose not to because he believed it was in his best interest to keep it.

3. Phillips’ actions are purely random. As it happens, he keeps the money for no particular reason. but if he encounters the same situation again he’s just as likely to return it.

Did Phillips make a choice? Not in any meaningful sense. He “chose” to keep the money in the same sense that a tossed coin might “choose” to come up heads, which is to say that he didn’t choose at all; his action just happened.

Note that the actions of Smith and Jones were caused, but the causes lay within themselves, and consequently they can be meaningfully said to have made a choice. But Phillips’ action was not caused by anything within himself (or if it was, the cause was simply that certain atoms happened to be arranged in a certain way at that particular moment), and therefore his action cannot be meaningfully called a choice.

These examples should make it clear that that meaningful choice depends on the choice being “caused” by one’s own character and personality as they bear on the situation at hand. To the extent that an act is uncaused, or caused by transient factors that just happened to cause the decision to go one way or another (but might have caused it to go the other way if it had come a second earlier or later) it is not a meaningful choice at all. Thus determinism would not be incompatible in the least with the ability to make meaningful choices.

elwoodblues

Things start getting really... weird when you get down to the molecular level. I mean, we imagine atoms as tiny points of mass in space. They have a definite position, a definite direction, and these things can be measured to an absolute. We just need better instruments, right?

Well, actually, as intuitive as the above is, it's also entirely false. As it turns out, particles do NOT have a real, absolute position in space. There are areas where you have a high probability of finding it, yes. But, weirdly enough, it seems that the particle doesn't have a position until we look for it, and then it 'collapses' into one position. As soon as we look away, the field of probability starts growing again.

Look, it's all too weird to explain over the web. Go find a good, popular book on quantum mechanics. Someone point madmax at a good one; I've never been able to find a simple, plain, easy to understand one (of course, maybe it doesn't exist...).