There are laws governing the motion of fluid flow and we can predict flow field with certain accuracy. I think there must be laws governing the motion of human beings. If so,what are the laws? If we get these laws down in mathematics,then can we predict our personal future using something like CFD?

"Difficult to tell... always in motion is the future"

- Yoda

another philosophical question... but this one can be answered quite easily: the matter (fluid) is "stupid" and thus obeys the laws of physics unlimitedly. we know the laws, we can predict the behavior fluid flow. people have self-determination. altough their bodies always obey laws of physics too, their minds obey no law at all. thus human decisions are not predictable. unpredictable decisions of minds cause unpredictable actions. altough the actions must comply with laws of physics, their occurence, location and instant are doubtful...

though, there exists some statistical models of human being and society behaviors trying to predict the society's future situation I am not sure how well they work. I think they need VERY MUCH improvement and daily correction of input parameters and "empirical factors" (in other words, "bulgarian constants" or "coefficients of ignorance")

Whomever comes reasonably close to accurately modeling human behavior in aggregate over the long term will make trillions of dollars in the stock market. People are working on it, but their models are woefully imprecise. As I observe human behavior every day in my clinic, I can assure you that irrationality rules the day in most people's personal health decisions. I don't forsee any good model of human behavior any time in the next few millenia.

To answer this question we must wait for quantum computing, and we need to introduce the idea of parallel universes.

This is kind of leaning away from Newtonian physics and bring us to quantum physics. I believe that this is not the only universe and the physics in this universe is influenced by other universes.

Perhaps there are governing equations in the "quantum since." By using string theory I believe that someday there will be "quantum-flow" equations which may predict the future of quantum states.

I think this would be a great thesis topic.

>>but this one can be answered quite easily

Who was that who said: "Every problem has a simple answer. Logical, plausible, and wrong." (or so)



I'm not saying your answer is wrong. I like it. But it's just not quite that simple.

>>their minds obey no law at all

Are you sure? Isn't every thought in your mind, and every emotion, just a complex interaction of matter and electrical impulses that flow through your body? Aren't these processes governed by laws of physics (even laws that we might not fully understand and grasp at this time?).

What does "unpredictable" actually mean? Is it sensible for error prone human beings to make an absolute statement on predictability? Doesn't the term "unpredictable" just emphasize the limits of our own understanding? Let's be humble and recognize that there is much left to learn about nature and about ourselves. It's far too early (borderline arrogant) to stick absolute labels on things, when we should really be aware of our own imperfections.

The question is not new at all, and the current understanding is that there really are certain things which are very difficult (if not impossible) to predict reliably. Much of nature can be explained by the good old deterministic philosophy, but chaos doesn't fit into that kind of thinking. Is the human brain chaotic?

It's kind of ironic that the human brain has learned so much about nature, but is struggling so hard to understand itself.

please accept my compliment mani, I'm clapping. good questions, great subjects for nice debate.

let's think of the application: how long time would it take for all people to come to psychologist to be examined such that a model of their behavior could be made? or how long would it take for all people to report their future actions to a research centre? until all the data would be processed, some people would die, some would be born, some would simply change their opinions - resulting model created at the centre would be wrong. is not it a beatiful example of ill-posed problem? what happens when solving ill-posed problem?

(btw, this reminds me the explanation of heisenberg's principle of uncertainity quite a lot)

well, I accept that the suggested approach is not just and that having different approach the problem would be seen in different light.

"God does not throw the dice when deciding on our universe" - surely not. but people do (imho).

Fluid motion cannot be predicted in general. The equations are well known, but they are sensitive to initial conditions. This is why weather men can't predict beyond the next few days. Humans are more complicated still.

Once again we need quantum technology to be able to predict the weather. This goes back to that parallel universe issue.

Quantum mechanics (or quantum computers if they ever happen!) will not solve the problem of weather prediction - unless you interpret the result of the simulation as a forecast in a parallel universe; i.e. the forecast is wrong in this universe but will be "right" in some parallel universe we don't know about (you could actually say this about current weather forecasts).

You may start by reading "Fundation" by I. Asimov.

For the moment quantum therory hold for a probabilistic theory, but is it really the case ? What, in my sense, we call 'Chaos', is a behaviour of an unpredictable system.

Why unpredictable ?

Simply because the accuracy of the measure of the initial condition, and all interaction during the evolution, is not attained.

If the really nature of quantum theory is probabilistic, all is lost for a good forecast... But if not, and if it stands for the lowest source of motion ( or interaction ), the brain and all other components of the universe should be predictable.

I'm now searching for the computer to do that...

Ha, ha ....

>the brain and all other components of the universe should be predictable

Theoretically, maybe... but there's a big difference between such idealized thought process and practice. If a system is really chaotic in the sense that infinitesimally different initial conditions lead to radically different solutions, you would need an absolutely perfect method (not just "accurate" but absolute zero error) to predict the behavior, provided that the initial condition is given exactly. The problem with chaos is that approximations are no good. You either get the exact solution or (likely) a completely wrong solution. Do you know of any principle of physics that can be claimed to be exact but is sophisticated enough to describe reasonably complex problems, not to mention an exact method for solving those problems, or a computer that could perform calculations with absolute zero error? And even if you had such a perfect setup (I'd call it "God in a box"), you would still need a method to obtain exact initial conditions in the first place. If you think that's feasable, Heisenberg will disagree with you. Even theoretically.

Heck, can you even predict who will be the last person to post to this thread?

As of now, me. Who could of predicted? However, there may be another person (other than me) in another universe who is actually writing this message. I predict that this will not be the last posting.

Yep, read the trilogy as a kid. And then the two sequels. And then the three prequels.

Now it turns out there's a second foundation trilogy. This is getting worse than Dune!

You know what, you're right!

The answer is 42! .-)