One of the branches of western philosophy is metaphysics, which asks about the nature of being and the world. It is the extension of what was once known as natural philosophy. Modern science is empirical natural philosophy. Instead of trying to answer questions about how the world is the way it is by thinking about it, it makes hypotheses and tests them experimentally or observationally. The late twentieth century was a time when physics, specifically string theory, drifted back towards metaphysics. String theorists attempt to answer questions about our reality by constructing theories that are mostly grounded on mathematically aesthetic principles. I have no real problem with string theory per se, except in its claim to be more “fundamental” than other branches of physics. As I have argued before (e.g. here), there are fundamental concepts at all energy and length scales.
What I will argue here is that we have been misguided in trying to reunite metaphysics with science. As I have argued before (e.g. here and here), it is not even simple to define what is meant by “fundamental laws” or a “theory of everything”. If our universe can be approximated arbitrarily accurately by a computable one (yes I know some of you disagree with this assertion), then what constitutes the underlying theory? Is it the program that generates the universe? Is it the most simple description (in which case it is not computable)? Or is it something else?
While metaphysics as science is a dead-end for me, metaphysics as mathematics is ripe for very interesting insights. Instead of asking directly about “our” reality, we should be asking about hypothetical realities. We should be doing philosophy of science and metaphysics on artificial worlds. This would then be a controlled situation. Instead of speculating about the underlying laws of our universe, we can simply specify a given set of properties in some hypothetical or simulated universe and probe the consequences. We can do this at arbitrary levels as well – universe, multiverse, meta-multiverse and so forth.
I think ironically that doing such a thing would give more insights into our universe than what we are doing now. For example, if we started to investigate what types of simulated worlds would generate life, it may inform us more about how probable life exists in our universe ( as well as force us to come up with some quantitative definitions for life) then sending out space probes (e.g. see here). It could also give us an idea of how variable life can be. We seem to be stuck on looking for biochemical life. Well maybe there are electromagnetic plasma life forms out there. If all it took to generate complex life-like objects was a nonlinear rule that didn’t blow up, then the answer to why our universe seems so well-tuned for us would be that any old rule would have worked although it would give entirely different looking life forms. Also, if we thought more about how we could generate or detect any type of consciousness in a simulation, that may help us better understand the consciousness we have.