Among the differences between an epistemology that actually works, i.e., one that gets us (closer) to the truth, and one that's bogus--a pseudo-epistemology--is that there is convergence of understanding in the former and divergence in the latter.
At the start, when we have yet to understand the nature of phenomenon X, there will be various possible, plausible, competing hypotheses/explanations for X. Our goal is to prune and throw out those which are wrong. We want to know which ones are false so we can reduce the number of feasible hypotheses. And this can only be done if there is a methodology for doing so.
In the epistemic realm nothing beats the methods of science for understanding reality. While there may be an infinity of possible, explanations for X, the methods of science allow us to rule out a massive amount of hypotheses. What remains are those that best explain the phenomenon in question and those that have the best predictive capacity. This is what I mean by convergence. Via science we converge toward the best/right explanation.
Theology (not limited to the Semitic traditions), on the other hand, is one prime example of a pursuit that results in divergence. Theology is pseudo-epistemology; it does not lead to any knowledge of reality. The number of theologies in the world is still increasing. And one reason for this is because theological hypotheses can't be tested. Unlike in science, they can't be disproved.1 This feature of nonfalsifiability is the Achilles heel of theological claims. It implies that they can never be known to be true.
Because science leads to epistemological convergence, we don't have a Xiamen chemistry that's different from Mumbai chemistry that's at odds with Manila chemistry that disagrees with Nairobi chemistry that's irreconcilable with Tehran chemistry that's .... And as far as we can tell the laws and theories in chemistry are the same on the Moon, Mars, Neptune, or for that matter, celestial objects a million light years away.
Contrast that with theology. Chinese, Indian, Philippine, African, Iranian, ... theologies have not in the past hundreds/thousands of years ever converged toward one theology. There has been no pruning of what isn't true. On the contrary, the opposite has been the norm. And to go beyond our little home, is it really believable that on planets dozens/hundreds/thousands/millions of light years away, where intelligent life forms have arisen as well, that any of their religions (if the organisms are genetically/psychologically/culturally predisposed to religion in the first place as we are) would be the same as any of the ones we have here? Will their deity and theology uncanny likeness to, say, Christianity?2 On the other hand, can you imagine a technologically savvy civilization on any planet that teaches physics that contradict ours? Can you imagine those extraterrestrial science professors teaching that atoms don't have protons, neutrons and electrons, that carbon cannot produce double bonds, that x-rays have a frequency lower than visible light, that the mass of an object remains constant even as it approaches the speed of light? 3 The findings of science are universal. The claims of religions are provincialist and culture-bound.
You know your epistemology is worth it if there's progress in your fund of knowledge, when what you say is true is in fact in accord with reality. And this can only be known if there is an objective way to test the claims. Theology has no such methodology. Its claims are mere speculations.
1. Some may think that this property of disprovability implies that the claim must therefore be true. But one example should suffice to illustrate how this certainly is not the case. Let's say I claim that there is a planet located 500,000 light years away. On this planet--which like ours revolves around a nearby star--lives a certain advanced species. By some technology they have been able to gather the works of various civilizations in star systems including ours. At this very moment a member of this species is writing a synopsis of Sagan's The Demon-Haunted World. Now I cannot prove this series of claims. But it also cannot be disproved. Even if there is a planet in the location in space where I say it is and even if we have a telescope powerful enough to resolve objects the size of mice, we still have to wait 500,000 years for the light from that planet to reach us. For all practical purposes the above claims are immune to disconfirmation. But it doesn't mean they are therefore true. On the contrary, we're apt to consider them implausible and give them a low probability rating.
2. You get a feeling of the provincialism and shortsightedness of, say, Christianity when you ask whether on other planets God had also incarnated and died and resurrected. It becomes comical once God stages the drama of incarnation-death-resurrection on every planet with pre-scientific civilizations. Moreover, Christianity tells us that humans are made in the image of their deity, but if life exists on other planets, given how evolution works, extraterrestrials will look pretty different from us and may even have very different personalities/psychologies. For the religions of the Earth better if intelligent life has and will never develop elsewhere in the universe. And better if the law of large numbers are not operative--given the huge number of planets in the billions of galaxies it is almost ridiculous to even suggest that the conditions for life existed and will exist only on Earth.
3. And even in those areas of scientific knowledge where indeed there is a discrepancy, human and extraterrestrial scientists can and will eventually converge on what is true. We--humans and aliens--can and will find out which of the hypotheses/explanations is the right one or the best one. The methods of science, whoever practices them, lead to testable, intersubjectively verifiable knowledge. Science works.
There is of course the question whether alien scientists would be employing some other methods which they call scientific but which we have not discovered/invented. As with "our" scientific method if it works it is naturally selected.