system
Given the following post, respond as if you're commenting on Reddit:
human
What are some arguments refuting the notion that empirical evidence is the only source of truth or facts?

A popular line of argumentation on reddit is that empirical evidence is the *only* source of truth or facts. Or that it *should or ought* be only source of truth or facts. Or that it is significantly "better"/more reliable than non-empirical evidence.

Then, based on these arguments, of course, they tend to lead to unremitting scientism. E.g. if the only worthy truth seeking is empirical in nature (which is the domain of science) and thus everything not science is not worthy.

What are some arguments against this line of thought?
gpt
>it should or ought be only source of truth or facts.

What is the source of *that* truth? 

Also, mathematics is a good counter-example. It is clearly *a priori*. Scientistic types will then have to appeal to formalist or analytic theories of mathematics in order to account for mathematical knowledge. But we know, after the foundational crisis in mathematics, that they are false.

Things that don't seem to be susceptible to empirical investigation, but we still think are factual, include:

1. Normative truths: moral obligations, epistemic obligations, etc. (E.g., "You ought to believe what you have net evidence for" or, "If you believe X, and you believe X --> Y, then you ought to believe Y." Indeed, if you are a defender of reason, logic, etc., as scientistic types take it that they are, then this essentially commits you to the objectivity of these kinds of normative facts which, incidentally, cannot be known on the basis of empirical observation or measurement.)
2. Modal truths
3. Mathematical truths

________________

See: 

* BonJour, *In Defense of Pure Reason* (1998). (This is one of the most rigorous and comprehensive defenses of rationalism.)

For a brief primer and easier discussion, you can also take a look at Huemer's *Approaching Infinity* (2016), particularly *Ch. 7, 7.3 Synthetic a priori knowledge*, ... and relevant sections after that.