With regards to a complicated system, l have found the following article whose link is below quite useful. From what l have understood partially is that, a deterministic system can be unpredictable because the uncertainty and the error in the initial measurement of the system will cause drastic change in the calculated outcome. — Wittgenstein

Thanks for the link. I downloaded the article and I've read through it quickly. I'll go back now and spend more time with it. It addresses issues I've thought a lot about in different terms than normally use.

My first take is that the idea that determinism and predictability are not the same isn't correct, or at least is not a useful distinction. As I said in an earlier post -

It feels intuitively to me that in some, many, most? cases unraveling cause is not possible even in theory. It's not just a case of being ignorant. Part of that feeling is a conviction that sufficiently complex systems, even those that are theoretically "caused," could not be unraveled with the fastest supercomputer operating for the life of the universe. There is a point, isn't there, where "completely outside the scope of human possibility" turns into "not possible even in theory." Seems to me there is. — T Clark

We can talk more after I've spent more time with the article.

That doesn't really undermine your point, but is "statistically deterministic" really what people mean when they say that something is caused? — T Clark

Yes i think that's one way to interpret the situation. Random uncaused events on the quantum scale average out to produce apparently deterministic events on the macro scale. We know with almost certainty that if you are hit by a car traveling at 100 mph you will die. However, unless I am mistaken here is a miniscule theoretical possibility that if all the electrons of both your body and the car were perfectly aligned a certain way, then the car would pass through your body.

Why not ? I am not a physicist but casually browsing about plank time, l think that we don't have any theory currently in physics ( that which combines relativity with QM ) to use any time period shorter than plank time. It doesn't imply that plank time is the shortest time period. — Wittgenstein

If there are no physical processes involving anything smaller than the Planck length then there could be no time interval shorter than the Planck time, no?

According to current theory Planck's the smallest that is physically possible. I am not denying that could change, but given the incredible success of QM it seems unlikely. Even if it is merely a limit to what we could ever measure, it would seem senseless to talk about anything beyond that limit.

Nicely put! Thank you for expressing it in that way, which I hadn't thought of. :up: — Pattern-chaser

:smile: