As explained here, epistemology properly studies objective truth criteria. And as noted elsewhere, the failure to explicitly identify proper truth criteria is ultimately devastating to one’s worldview - and therefore to one’s life. I have over-viewed some of the problems in modern epistemological theories (both Christian and other), but I have yet to put forward details regarding my own epistemological theory. While it certainly cannot all be covered in one post, the following is a very general outline of a proper epistemology for a rational and objective worldview.
I have broken the fundamentals of epistemology into the following basic categories. The failure to properly identify and differentiate between these categories has led to a majority of the problems in modern epistemological theory. My hopeful expectation is that the following breakdown will clear up a large amount of unnecessary confusion surrounding many epistemological issues. There are 3 primary categories of ideas, and a few sub-categories:
1) Logically Impossible -- Always False
An idea which is logically impossible is an idea which violates the basic laws of logic; an idea which is inherently contradictory. It is any instance of A being non-A at the same time and in the same relationship. Examples are “married bachelors”, “square circles”, “there is no objective truth”, etc... Such ideas are contradictions - and as such, are logically impossible. There is no combination of circumstances in reality which could allow them to ever be true. Therefore, you can know that if you come across a logically impossible idea (a contradiction), it will always be false. All logically impossible ideas are always false - because they are impossible.
2) Logically Necessary -- Always True
This is the crucial category which most philosophical thinkers (including Objectivists) seem to miss - at their own peril. Most people assume that logic can only tell you whether an idea is possible or impossible (Categories 3 & 1), and that you must use further means of analysis to establish whether a possible idea is true (see Category 3). But this isn’t always the case. There are some ideas which can be identified as true by the simple use of logic (apart from further empirical analysis) - ideas which are logically necessary. A logically necessary idea is an idea which cannot be denied without committing a contradiction. Let me give an example: I mentioned above that the idea of “square circles” existing is impossible, because it is illogical - it’s a contradiction. But if that idea is utterly impossible, then its opposite must be true: “Square circles do not exist”. The first category takes contradictory statements like “square circles might exist”, and determines them to be logically impossible - and therefore false. The second category can then take the conclusion of the first category in order to form a an idea which is necessarily true about reality: “Square circles do not exist”. Now do the same with the others: “Married bachelors do not exist”; “there is objective truth”. These are logically necessary ideas. They are always true because they must be true - they cannot not be true. Their non-truth is impossible. Such is the case with many of the most fundamental ideas to a worldview - such as “A is A” and “God exists”. I know you’re going to hate me, but I am not going to prove those examples to you, here - those are for future works.
3) Logically Possible -- Unknown, Thus far
The third category is the Logically Possible. This is every idea which does not fall into either of the first two categories -- every idea which is neither logically impossible nor logically necessary. These ideas are possible, but not necessarily true. The only way to confirm that any of these ideas are true or false is by the use of further analysis: empirical analysis. 1,000 years ago, as far as men in Europe knew, a great new continent across the Atlantic ocean was possible, but they did not yet know that it actually existed - and they wouldn't until they discovered it; until they saw evidence of it; until they empirically verified it. Because the truthfulness of the ideas in this category, in and of themselves, cannot be known, this category has a few sub-categories:
3-a) Logically Possible and Empirically verified -- Known, True
The first sub-category is the empirically verified. Ideas in this category are ideas which are logically possible and have been empirically verified - like the example of the North American continent above. Notice that these ideas are first logically possible and then empirically verified. There cannot be an empirically verified idea which is logically impossible because a logically impossible idea is not possible. For example, someone may think that he has empirically verified a square circle (maybe he has some psychedelic drawing put together by some advanced computer design program). No matter how much he thinks he has discovered a square circle, he is mistaken. It may be an object which is square in some way and circular in another - but it cannot be square and circular in the same respects. Why? Because contradictions do not (and cannot) exist.
3-b) Logically Possible and Not Empirically verified -- Unknown Thus far, Possibly True/ Possibly False
As indicated by the name, the ideas in this sub-category are likewise logically possible, but are not yet empirically verified and therefore cannot be considered to be true to our knowledge. I do not say that they should be considered false, because that would be assuming more information than is actually available. Neither do I say the rather silly (and contradictory) thing that Objectivists tend to say: that these ideas are “neither true, nor false”. Every idea is either true or false - whether we know it or not. There is no third category. When we don’t know, honesty behooves us to simply say “we don’t know” and then do our best to follow the proper means of finding out.
There are likely other sub-categories which could be added here (dealing with things like probability), and there is surely much more that needs to be said regarding each of these categories, but that exceeds present purposes. The above should be a very sufficient starting point for analyzing the validity of ideas based on these general, rational epistemological foundations. Stay tuned for further detail on each!
Note: In order to curb the Objectivist accusations, I want to make it very clear upfront that I have read Leonard Peikoff’s Analytic-Synthetic Dichotomy (and it should go without saying that I have also read Ayn Rand’s Introduction to Objectivist Epistemology). Peikoff’s work is particularly relevant to this post - as I’m sure many Objectivist are eager to point out. I’ve got much to say about his treatment of the subject, but for now I will only say this: His aims are noble, but his method and conclusions are atrocious. Or, to put it another way: “his diagnosis is good, but his medicine’ll kill ya”.