Greta:
Gosh, that conversation moved on quickly. Steve and DM, is it still worth replying to earlier posts or will that confuse things?
I'd say it is. If I've been away and the conversation has moved on I try, as far as available time allows, to look back and see if anybody has said anything that it looks like they want me to reply to.
Greta:
An entity that is neither subject to time nor space. This is what life needs to evolve to become if it is to survive the final challenges thrown at it by the universe. It's easy to imagine that somewhere, sometime in the history of the universe there will come a branch of life that survives "the great filter" and, one by one, keeps solving the challenges of existence - the death of their planet, of their star, the disruption of their local galactic neighbourhood, the disruption of their galaxy and its eventual annihilation. Eventually the only way would be to no longer be dependent on matter, to be capable of living in and from spacetime itself.
A curious thought (that concluding sentence). But if, as some people would say, the concept of space-time is a model that exists inside our own heads which is useful for explaining our observations of the way various objects move around and interact with each other, what then?
Greta:
The models are also, by design, an underestimation of reality's richness. All we have are sketchy models. I respect and would not contradict theories as they have been tested by great minds, but scientific theories are not designed to tell us what is actually real, they tell us the most recent steps in the shared reliable information that we've worked out about reality so far.
Here we're drifting back to a discussion of Idealism, Empiricism etc. Yes, it is a defining feature of models that they are incomplete - that they model a
subset of our observations and neglect others for the sake of simplicity. I don't think you have to refrain from contradicting them. Just contradict them by pointing out where they don't reflect a particular observation and where, therefore, another model might be useful. For example, Newton's theory of Universal Gravitation was a venerable model, and still is. But it doesn't accurately describe a particular aspect of the orbit of the planet Mercury (its perihelion precession) hence the invention of another useful model that does - General Relativity. And hence the invention of the concept called space-time.
Greta:
However, we are thrust into this existential situation of having to work out how to live our lives, which are not long enough to gain sufficient information or wait for science's answers. That means sharing ideas about the possible big picture, even if those ideas are not provable at this stage.
As has been discussed recently in the context of "how" questions versus "why" questions, I think the problem of working out how to live our lives isn't going to be solved by some future scientific theory. So there's nothing to wait for there. We might as well decide how to live our lives now, if we can.
I would think that if observation without prejudice had not been practised thousands of years ago, we'd still be living in caves. That is simply what brought us to this point. However, the myth of truly objective observation has been contradicted by QM. A system is not just a system but a larger system that includes the observer, including all of the sensory limits.
Yes, but I think one thing that QM taught us was that there were still prejudices - mental models that we learn from a very young age that turn out not to be universally applicable and, indeed, misleading when we're searching for ways to describe and predict some classes of observations. Yes, the idea that observation is a detached activity in which the observer's role can be neglected (an idea that always existed) was solidified into a
fundamental principle by QM.
A prejudice test: a recent experiment suggests that gravity does not impact on quantum spin. Assuming that the tests are duplicated independently enough times showing that QM and relativity truly cannot be reconciled, then would you then agree that dualism would then logically be true?
Dualism in the sense that there might, at a fundamental level, be more than one core principle of physics and that they might be forever separate? i.e. the loss of the concept of "Grand Unification"? Yes, if that's where the evidence leads. But it is interesting, isn't it, to ponder why we have that prejudice - that hunch - which tells us that there must be a single unifying principle to the universe? A kind of aversion to mess. That's why it was so disconcerting to many people when the nice neat models of particle physics started to get messed up with loads of new particles - a whole menagerie of them - a few decades ago. Or as a well known physicist said (in a restaurant analogy):
"Who ordered that?"
-- Updated Sat Sep 16, 2017 12:01 pm to add the following --
Correction of a typo:
When I said this:
Yes, the idea that observation is a detached activity in which the observer's role can be neglected (an idea that always existed) was solidified into a fundamental principle by QM.
I meant this:
Yes, the idea that observation is not a detached activity in which the observer's role can be neglected (an idea that always existed) was solidified into a fundamental principle by QM.