Imagist
Worshipper of Athe.
We "know" things based on experience and knowledge --agreed? If the rattlesnake has bitten and caused no harm, then the knowledge of reality is that the rattlesnake has bitten and caused no harm. To extrapolate that claim is to either make a prediction or a generalization, both of which do not represent "knowledge", at least not well.
I agree that we know things based on experience and knowledge; however, the reason I gave the specific example was that it is from the real world - many people each year pick up rattlesnakes and other poisonous snakes, due to the following verse:
Mark 16:18 said:they will pick up snakes with their hands; and when they drink deadly poison, it will not hurt them at all; they will place their hands on sick people, and they will get well."
These people are often bitten and die of poison. These people claim to know that the snake's venom will not harm them, but in reality, they don't know anything of the sort. They may have had an experience of religious ecstasy, but to extrapolate from that all their other beliefs is obviously incorrect and, in this case, very harmful.
In contrast, I am aware of the general perception that rattlesnakes are poisonous, and the only reliable way to not die from a rattlesnake's bite is to avoid them (which doesn't include picking them up). This belief is based in evidence, though perhaps not very rigorous. If more rigorous evidence were needed, I am sure that I could find medical studies rather easily.
As for camel urine, if it has demonstrated itself to be a useful medicine in the past then I have no problem with declaring it to be "known" useful medicine (of course, my opinion of medicines in general is pretty low: camel urine may actually rate above some of them).
Again, this is a real life example: in a particular Hadith, Muhammed describes camel urine as being a useful medicine. Admittedly, most Muslims I have talked to about this take the reasonable stance that the Hadith is unreliable, but amazingly, many Muslims actually defend the prophet, claiming that camel urine has medicinal value! If anyone were to act on this belief, the results would certainly be harmful. In reality, camel urine is not only useless and medicine, but it is cytotoxic, meaning that it kills cells with which is comes in contact.
Your question, to me, looks like you are asking me to specify a quantity to how much I have experienced and learned in my life-time. I suspect, though, that you are asking where should the line be drawn in defining what qualifies as knowledge, and that has to be further qualified by what it is "to know". As I said above, the prediction and the generalization are two examples of things that do not represent "knowledge" well, even though we can rely on them to "know" reality. It's a good question, that I will think more about.
Perhaps I haven't been clear. I'm really asking the question in the context of faith: if we determine faith as a reasonable measure of whether something is knowledge, how do we determine what to have faith in? How does one determine that a virgin birth happened but it's not okay to handle rattlesnakes? How does one determine that it's right for women to wear burkas but that camel urine is a weak poison, not a medicine?