There are only two kinds of "knowledge" for me personally:
1. Realized knowledge | the information which I've gained throughout all the experiences of my life, through whatever means: sensory, intuition, etc.
2. Potential knowledge | all that I have yet to experience.
Estimated Ratio of potential to realized knowledge in my life: 99.999999 : 0.000001
Notice that I don't give any valuations at all for either group. That's because I automatically consider almost all information/experience to be basically true, good & beautiful. (The exception would be when the source is a liberal…but then we're talking knowledge here…) Of course not all information/experience is ultimately true, good and beautiful.
So how do I know what in this great mess of information/experiences needs to be valued, and what needs to be discarded? Well, to be quite honest, it really depends upon how I feel about the information/experience.
At this point let me state that for me there is a significant difference between emotions and feelings. I would define emotions as they would be commonly understood, the agitations of our being that often have physical manifestations like crying, laughing, and so on. But feelings I define more like awareness or consciousness; there is a definite link to emotions, but from my perspective, emotions proceed forth out of feelings, not vice versa.
I cannot help but notice that almost all information/experiences have an impact on my feelings. The impact is either positive (pleasurable), neutral, or negative (painful).
Information/experiences that I value are those that bring forth pleasure of some sort. Information/experiences that I would rather forget have brought forth feelings of pain or suffering. And then there's a whole lot of stuff that is somewhere in between, neither all that painful nor pleasurable.
Of course, this is all entirely subjective. I can communicate my feelings to someone else, but I certainly can't force someone to feel the way I do. Nor can I prove my feelings using math, logic, or anything else. They just are. Whether or not anyone else perceives my particular feelings is ultimately meaningless; for I can certainly perceive my own feelings, and to a certain extent even measure their intensity. But don't ask me to explain it to your understanding or prove it to you, it's simply not possible. At best I can communicate my feelings, often imperfectly, and hope that the receptor has the ability to properly interpret what it is I'm communicating. (Amazingly enough, this isn't so hard as it seems, assuming the receptor also has feelings!)
So I can communicate my information/experiences to someone else, perhaps even "prove" them to a certain extent, but so what? Some people will believe anything with no proofs what-so-ever, other won't believe anything no matter how many "proofs" you give them. It's not that people are irrational, it's just that if someone feels good about your explanation, they'll buy it. If they don't feel good about it, then they aren't going to be convinced no matter what. We are not just a bunch of ultra-rational computers testing each and every bit of data that comes are way: our feelings often seem to be the only real test thjat we actually use.
Another problem is that my feelings may or may not lead me to ultimate truth. Yet, I don't really believe that I'm going to find ultimate truth in this life anyway. I can easily settle for approximate truth for a vast majority of my purposes (apologies to Kierkegaard). I don't need to know the biology of the coffee plant or the inner workings of the coffee industry to enjoy my cup of java in the morning.
As for rational thought, I find it to be most useful as a means of categorizing all my various information/experiences. My rational thought process (what little there is of it) simply makes some quick little logical determinations about the knowledge/experience, then stores them away for later processing. Most of this happens in the background, unconsciously. Again, for a vast majority of my purposes, this background processing is all that is needed.
My rational mind also serves to test & process particular types of information/experience depending upon my feeling that further analysis is necessary. The rational mind then works the problem until it feels right. Then the problem & solution gets placed back in their little pigeon-hole somewhere in my memory, often only to be eventually forgotten--erased from memory. So the very core of my being is nothing more than a lump of feelings, or awareness. All the rational-minded stuff is actually in service to my feelings, not vice-versa. And I have a feeling that this is true for more people than just me, no matter how much they trumpet their superior rationality, as if they were the very incarnation of Mr. Spock.
And speaking of Star Trek analogies, I find my rational thought process is often most fully engaged when having to deal with other people, whether it is through personal contact, books, lectures, or whatever. Then I used my rational processes like the shields on the starship Enterprise: they guard my feelings by filtering all the garbage that often comes forth from human beings, and categorizing it appropriately a priori, before it gets to the core feeling level. The information/experiences deemed worthy is then passed on to my feeling mechanism (believe it or not, I have read such a thing does actually exist in the brain!) And then it's my feelings which ultimately decide what to do with the information/experience. Of course, there are times when I don't want my rational mind to get involved with my experiences at all, because the experiences might be bringing me quite a bit of pleasure! At that point, logical analysis only gets in the way.
Come to think of it, a huge chunk of my daily living needs little to no rational analysis. Normally it only comes into play when another of my fellow human being says they've found THE TRUTH, and that's when the real fun begins...
THE BIG QUANDRY
Now here is the biggest problem I face: the information/experience that I find the most valuable of all, that which I'm willing to die for, is almost entirely subjective. I cannot "prove" it to someone else. Of course I've proven the value of this information to myself, and have no doubts about it what-so-ever. I can even say I'm completely certain that it's true, good, wonderful, etc. Yet, because it is somewhat beyond the scope of the five senses to study and observe, regular, physical proofs are impossible.
It's like going to Florida, and then explaining to your friend in North Dakota what Florida is like. You can tell him everything about it in great detail, but you cannot really "prove" there is a Florida until your friend has experienced the place for himself.
That brings up the interesting problem of just how much of our "knowledge" is really just the belief in other's testimonies. How can we really "know" something until we ourselves have experienced it? Just how much of that which we hold dear is just what "feels" right? I think many people would be very embarrassed at how much of their "knowledge" is based on nothing more than good feelings, or even bad feelings!
Well, since there are no right or wrong answers, there you have it! And of course you can neither prove or disprove anything I've just posted, since it's all just my subjective musings anyway…