I'm not sure you and I are using "theory" the same way. I don't see a scientific theory, e.g. general relativity, as a metaphysical entity. Theories have truth value. For me, the scientific method is a metaphysical entity. Perhaps that includes the methods by which theories are developed and verified. I'll have to think about that. — T Clark
I started posting on this forum to discuss the big issues of Metaphysics, not the mundane details of Physics. But, in all too many threads, a stalled discussion turns to challenges of "what can you prove?", instead of "what is reasonable?" Metaphysics, in my opinion, is supposed to be focused on ideas that literally
transcend the scope of empirical scientific methods, such as "what caused the Big Bang?" There is no way for us to know for sure about the time before Time, or a place outside of Space. As philosophers, all we can do is to make educated guesses, and then test them against the critical faculties of other educated guessers. The result will not be absolute Truth, but it may get us closer to truth.
Those educated guesses are what we call "Hypotheses", and when some guesses survive the scrutiny of peers, or lead to some replicable evidence, we may even call them "Theories". But even the best of our Theories, such as Thermodynamics and Evolution, are based on incomplete evidence. Hence, they are subject to falsification or revision in the future*1. Consequently, understanding the difference between Theory and Practice is essential to my understanding of Meta-Physics. A theory may-or-may-not have truth value, but only when it is put into practice will we know which. For example, Darwin's Theory of the Origin of Species has been tested and proven accurate regarding
adaptation to a changing environment. But after two centuries, evidence for divergent
speciation has been iffy. *2 Likewise, Quantum Theory violates many of our reasonable intuitions, yet some of the mathematical models can be proven in practice.*3 So, we are sometimes forced to accept facts that defy common sense. And we have to adapt our incomplete theories over time.*4
My point is that a Theory is a "metaphysical entity" --- a meme in a mind, not a thing in the real world. A
bird is a physical thing, but a
species of birds is a mental category. General concepts and Universal Properties are Meta-Physical, according to the same categorical distinction between a Mental Meme and a Physical Gene. A theory is a model or map, not the physical thing or terrain. That's why I think it's important to differentiate between meta-physical theories and physical testing, between metaphysical "methods" (Philosophy) and physical methods (Science). Unscientific conjectures, such as Multiverses & Many Worlds, cannot be verified empirically, because they go beyond the physical limits of the Real World, into the Ideal Realm of Meta-Physics. *5
To many posters on this forum though, the distinction between Physics and Metaphysics is like the post-enlightenment political division between rational methodical
Science and irrational mythical
Religion. But that's not what I mean when I use the hyphenated term "Meta-Physics". By that I simply refer to the same difference that Descartes formalized between a physical Brain and a metaphysical Mind. A material Brain can be studied empirically, while the immaterial Mind can only be studied metaphorically. That's why the Behaviorism trend in Psychology was so brief. They soon realized that documenting physical actions was not the same as verifying mental intentions. Their hypothetical inferences often depended on the personal subjective biases of the observer. So, their "verifications" consisted mainly of confirming bias. That's why both Scientific and Philosophical models are subject to Peer Review. Only by comparing the "theories" of several observers can the errors be canceled out.
In my theory of Philosophy, Meta-Physics is about models and theories that are not currently verifiable. They can only be determined to be reasonable or not, based on Logic and incomplete evidence. And that requires Wisdom. Yet, we can't even define that term objectively, even though we may know it subjectively when we see it*6. So, let's not play the "show me the evidence" card, when the game is non-linear and open-ended.
*1
Superseded theories in science :
https://en.wikipedia.org/wiki/Supersede ... in_science
.
*2
Adaptation vs Speciation :
A new bird species that is only slightly different from others of the Finch family. So, it's more like evidence of adaptation, than of something entirely novel.
https://www.sciencealert.com/darwin-s-f ... -galapagos
*3 "The verbal interpretation, on the other hand, i.e. the metaphysics of quantum physics, is on far less solid ground. In fact, in more than forty years physicists have not been able to provide a clear metaphysical model. "
___Erwin Schrodinger
*4 “It is impossible that there should be demonstration of absolutely everything; [for then] there would be an infinite regress, so that there would still be no demonstration.”
― Aristotle, Metaphysics
*5 "Nature is under no obligation to conform to our mathematical ideas—even the most brilliant ones"
___Avi Loeb, Astronomer
*6 "The phrase "I know it when I see it" is a colloquial expression by which a speaker attempts to categorize an observable fact or event, although the category is subjective or lacks clearly defined parameters".
https://en.wikipedia.org/wiki/I_know_it_when_I_see_it
“The devotee of myth is in a way a philosopher, for myth is made up of things that cause wonder."
― Aristotle , Metaphysics
"He, however, who begins with Metaphysics, will not only become confused in matters of religion, but will fall into complete infidelity."
___ Maimonides