Paul Martin said:
It is conceivable that the number of such blocks might be limited to some number like 11, as speculated both by Plato and by some string theorists.
AnssiH said:
Well, I must say I certainly have never been able to conceive any way to make it work without adding any "dynamic" component somewhere one way or another.
I agree. Maybe we can talk about what that "dynamic" component might be.
AnssiH said:
If you decrease the number of "pointers" in each higher dimension, then wouldn't it just mean that the "upmost" pointer is pointing to the rest of reality, "all the time"?
Yes. But I don't think that poses an insoluble problem. If the "rest of reality" were a hierarchical nested set of static space-time blocks (MWI), then the pointer would be pointing at it (into it) "all the time".
AnssiH said:
I've said it many times in this forum that once I've tried to reconcile spacetime with the philosophy of the mind, it has become by far the most elegant option to assume that reality really is in motion, and metaphysically so.
I agree with your view here. But, it leaves us with the questions of what exactly is it in, or about, reality that is in motion? And what, exactly, is motion itself? I'd like to explore those questions a little deeper.
AnssiH said:
Yeah, and certainly it can be questioned whether even in this case the extra dimensions should even be imagined as if they are spatial dimensions, after all they are very different from the three we are familiar with.
I think this is a good question to begin with. What is a spatial dimension, and whatever it is, is it the only reasonable candidate for the extra dimensions?
Please correct any of this analysis, but this is the way I see it: A dimension is a degree of freedom. Thus, we may have not only spatial dimensions with position as the variable, but we may have dimensions of color, or energy density, or other variables.
It doesn't seem reasonable to consider change in color or temperature or other non-spatial variable to be motion. So, we could define 'motion' to be a change in position by an entity (the thing that is in motion). The "thing", as you point out, seems to be a stable pattern of some sort. With this definition, we require the "thing" that is in motion, and at least one spatial dimension. So "motion" is the process of the "thing" occupying successively different positions in a spatial dimension.
Now, let's ask what that "thing" might be. Can we say, for example, that a graph of the function y = x is in motion? Well, no, it is static. How about considering a short segment of the ink mark on the graph to be a "stable pattern", and we notice that for different positions of x, the "stable pattern" changes to a different position vertically. Is that motion? I think it makes no sense to say so. But what if you observe that graph, and your eyes and your attention follow the ink line from the origin up to the right some distance. Is that motion? Well, yes it is. At least your eyeballs moved. But more importantly, your subjective conscious experience of attending to the successive ink mark segments not only gave you the illusion of motion, but the experience was along the lines of what we usually associate with motion.
Thus it seems that, continuing with my suggestion above, if the "rest of reality" were a hierarchical nested set of static space-time blocks (MWI), and the pointer is pointing at it (into it) "all the time", the "illusion" of motion, and the necessary conditions for QM and GR would be satisfied if the pointer follows world lines within the various blocks.
The pointer would serve as the observer and would somehow determine which, or how many, of the optional branches to take at each encountered quantum event. Whether the pointer splits and becomes several, each following a world line in a different one of the MWs, or whether the pointer has the free will to choose one over the others, or whether there is some deterministic random algorithm which makes the choice, would be questions for further investigation, but that wouldn't change the ontological or the physical explanation, it seems to me.
AnssiH said:
Basically, if you assume a learning system that initially doesn't have any pre-conceived idea of reality at all, it is forced to form some idea of reality by making assumptions about "what exists" and by building an association network that is basically system's own conception of the world; its worldview. (And the only way to build a worldview without anything to begin with is to build concepts that can be placed in juxtaposition with each others, such as "space" is what "matter" is not, and vice versa...)
The worldview that results is not something that has its root in some fundamental truths, but rather it is a self-supported circle of beliefs. ... This is all what would result if a system must learn without any prior knowledge about reality. Such a system can never quite be certain of the ontological nature of its own reality either.
I agree completely. But what exactly is this "learning system"? Let me suggest some possibilities.
For starters, we have the living human brain. You have already explained how the brain builds a worldview just as you described above.
Next, we can imagine sophisticated robots that are probably going to be built in the not-too-distant future, which will be set to work exploring heretofore unreachable parts of our universe, such as nano- and micro-scale environments, deep space, deep oceans, etc. And, as you point out, regardless of what they learn about their respective environments, they "can never quite be certain of the ontological nature of [their] own reality."
Next, going backward in time, we can consider the most primitive precursors of life on Earth as being such "learning systems". Everything you said above applies to them as well, as it does to all their progeny, including us.
Finally, going back even further in time, we can ask whether the most primordial, or fundamental ontological entity, whatever it was, might not also have the same characteristic of being a "learning system". It makes sense to me that it might, and it seems to me that it might be fruitful to investigate the consequences of this hypothesis. What do you think?
In your post #107 in Quantum Physics>Against "Realism", you wrote,
AnssiH said:
You may be tempted to say "maybe MWI is just this idea", but to me MWI is like all the other interpretations, and they are basically arguing about whether everything is made out of "earth, air, water and fire" or from "solid, liquid and gas", or perhaps the fundamentals are "opaque" and "transparent" matterpieces, when they should be concentrating on much much deeper issues. Something like, how could inertia be fundamental? Think about that.
I have thought about it. It seems to me that an "ability to know", i.e., a "learning system" could be fundamental. It seems less complex than, say, assuming something like energy (the ability to do work), or a field (the ability to force), or a set of laws (the ability to prescribe), is fundamental. What do you think about that?
In that same thread, you wrote,
AnssiH said:
I don't think anyone has been able to actually make any explanation about how the "illusion of flow of time" could be achieved if nothing is in motion in reality, but everybody are very willing to dismiss the whole problem as meaningless because you really don't bump into it until you get to the philosophy of the mind, which may seem unrelated to physics, but it is not.
So you could say my belief is that we just haven't figured out the proper model yet, but that we are capable of doing so by letting go certain particularly sticky assumptions about reality.
Let me try. If we let go of all assumptions except for the existence of a primordial "learning system", (AKA "an ability to know", "an ability to realize", "a receptive principle", "pointer") we can imagine an evolutionary scenario in which "the "illusion of flow of time" could be achieved if nothing is in motion in reality..." Here's how:
This "learning system" exists (by hypothesis). Therefore, something and not nothing exists. Therefore that fact also exists. The "learning system" has the "ability to know", so it is reasonable to conclude that it might know that single fact (i.e. that something exists). (Even at this beginning point, your observation is well taken, that the "system can never quite be certain of the ontological nature of its own reality", so the "learning system" might know that something exists, but it can't know the nature of the "learning system" itself.)
The fact that a fact is known is a new fact, which could then be known. Similarly, a large set of facts, or information could be generated and developed. (I'm not exactly sure how, but I think it could be worked out.) This set of information, together with the "learning system" itself, would comprise reality. If the "learning system" could act as a "pointer", by successively attending to various details of that set of information (like stable patterns in it), then "the "illusion of flow of time" could be achieved [even though] nothing is in motion in reality".
It should be noticed that in this model, even though nothing in reality is in motion, there is an evolution going on: new information is being added. This is consistent with the part of reality we observe (our universe) in that it already contains a sizeable amount of information and if we consider the present moment of any worldline to be a temporal boundary, it seems that this boundary continues to recede (procede?) into the future.
So reality, as you suggested, really is in motion, but the real motion is only in the "pointer" and not the MWI blocks. I suppose you could also say that the growth of the blocks is motion in the same way that the growth of a coral reef could be said to be motion. The reef is static, but the boundaries move.
I am eager to hear your thoughts on these ideas.
Warm regards,
Paul