You have identified a reason to believe in mathematics.
You are abstracting way too much meaning when you are talking about complex frameworks as a monolithic "thing" that we believe or we don't. That's actually fairly unreasonable to do.
Mathematics is not a monolith. There's plenty of internal arguments as to which parts of Mathematics belong in that category, and which don't, and how these map to reality. There's mathematical realism, there's anti-realism, formalism, etc.
But, in terms of the "internal logic" and internal semantics of either of these views, "reasonable belief" only extends to these as far as how useful these are in reality when it comes to pragmatic applications of these frameworks.
There are plenty of scientific and philosophical frameworks that are not worthy of being believed on, because these don't present any pragmatic usefulness. Our belief systems are always evaluated in context of pragmatic utility of these beliefs.
You keep lobbing vague statements at me, like, "Christianity is perfectly reasonable because it maps to a vast history and network of meaning that structured the stories and preferred behavioral patterns that it presents." Nothing about that statement makes Christianity true. Absolutely nothing.
And you keep lobbing oversimplified semantics to the likes of "show me that Christianity is reasonable apart from it's pragmatic application", which you seem to somehow perceive as "Christianity is true" in such and only such context. It's an absurd request.
The word "true" only works inside "internal logic" that
we frame. For example, if I show you a picture of apple and say "This is a picture of apple" ... that statement is true, because we share and agree on a
communication framework that maps certain meaning to certain reality. Thus, if we call what we refer to apple as something else, then that statement would no longer be true. It doesn't change what the apple IS "out there" beyond what we refer to it. It only forms our "collective frame reference" that we use as communication framework to communicate certain patterns and function of these patterns. We then use these models to build tools, talk to each other, and recognize certain complex patterns that allow us to predict the future.
Such is the case with every framework we use, be it mathematics, physical sciences, philosophy, sociology, economics,
and religion .
We separate these into distinct categories, but these don't exist as such in our functional brain.
So, when it boils down to it, what you are REALLY ASKING ME, is
to show you that this particular function of a brain is "true", and it's an absurd request. You are looking at these things backwards,
as you brain abstracts these into patterns that you recognize. So, then you say "this is religion", "this is math", "this is science". In reality, there's only a collective network of brain function that:
1) Reads environment
2) Compares it to the existing model of the environment
3) Determines the adequate course of actions that are driven by the model
4) If no model exists, then it uses try/fail method to make choices and formulate a model
5) It then communicates that model to other brains for comparison and benefit of the collective being
THAT MODEL IS COMPREHENSIVE. You only see "science", "religion", and "communism", because you recognize certain distinct patterns... and that's how our brain works when it comes to perceiving reality. It works by filtering through chaos in search for patterns.
That's all we've got, and that's all we'll ever have. What you would call "true" in this process
is purely pragmatic label that we derive based on observed outcome of adopting some model. And that process of "adotion" is always environmentally-driven. That's why we have word "In-formation", because it's a flow of signals that "froms" your cognitive interpretation from inside.
So, given the above, you have to see why your request is absurd.
At best, if you can follow that topic sentence with the facts and examples that readers were expecting, then you can have an argument for why practicing Christianity is reasonable. But I have not seen a shred of a thread to show me why believing Christianity is reasonable, and I'm wondering if you even have any inclination to even try.
Your request is severely unreasonable, because you are abstracting "belief" as some sort of function that exists separate from pragmatic function of our brain. You can't point to our brain neurons and say "hey... there's that false religious belief there, and here is this true science". It never exists as such.
In terms of our neuro-physiology, there's a network of complex signals that's reduced and filtered to "likely match".
The reason why a child recognizes a rectangle with two circles as a "car", is because that's how your brain stores the meaning of the car. It reduces details to simple concepts that either "hit" or "miss", and you end up with an abstract model of reality. It's very pragmatic.
So, what you are calling Christianity, on the level of the brain is a similar neural network of abstract "hits" and "misses" that maps to the pragmatic and functional meaning of reality.
So, what you are really asking me is to map my network of meaning (solidified through neural pathways) to your network of meaning in such a way that would trigger the same "valid" response
in context of your brain network.
So, what I'm saying is that believing in Christianity is only reasonable is:
1) If your brain maps to reality using the framework that Christianity provides
OR
2) If I provide with some meaningful and analogous interface that would map similar meaning in context of your current existing framework
I can't demonstrate the Chrstianity as reasonable on the level of "mapped meaning of scientific reductionism",
YET
That's what you are forcing this conversation into without any a-priori demonstration that I should accept scientific reductionism as an adequate framework for interpreting reality... and you are
justifying it solely via pragmatic applications of that framework.
So, you say something to the likes of "but science gives us a lot, what did religion give us"? And when I point out what religion gave us, you say "All you demonstrated that practicing religion is reasonable, but you need to show that believing in it is reasonable also". So, you switch and bate the contextual semantics here.
Thus what you are saying is "Please show me that X is true, using my maps of meaning", but when I ask you to demonstrate something as simple as time in your existing maps of meaning... you can't. You appeal to universal axiomatic, and necessary assumptions and you just run with it as valid and useful.
That's what religion is. You can't separate pragmatic aspects of it from what you would call as "truth". The meaning simply doesn't map to the same thing that it does in your framework. But it doesn't make it "less true" when we frame that meaning against, let's say ... mine.
Thus, it's easy to debate people who map to primitive and literal meaning of religious concepts. And that's what you seem to do,
to which cudos to you! We need that.
But, in process you seem to ignore that there is a broader framework of meaning that does work, and that without it we wouldn't have science, we would not have functional societies. And that's an easily demonstrable fact.