One lesson of Post-modernism is that you can't know everything with certainty. I have a friend in my writing group (with whom I share a first name) who takes that to mean you can't know anything for sure. And I disagree with that. There are some things you know for certain, but the edges can get a little fuzzy. No problem with that, really. We know that two plus two is four. And we know you can define Galois Fields of order 4 where two plus two is zero. And we know that two apples plus two bananas almost equals one fruit salad.
I have heard it said, "you can't put God in a box," and that's true. But does that mean we can know nothing of deity? I think not. I think there are some things about God that are certain and there are lots of things that get a little fuzzy. It's a mistake to insist that we know things for certain that the Bible is silent about or only obliquely touch upon.
A good example is evolution versus creation. I'm of the mind that takes whatever the Bible says as certainly true. I'm also of the opinion that most fossils are not fakes like the Piltdown Man bones. (However, you'll note that there's always a risk of being taken in by a fake fossil, given what we saw in Piltdown.) I am also of the opinion that I make mistakes and so do all humans now and then. The job of the scientist and of the theologian is to take whatever's known and try to construct a coherent logical framework that explains it. This is a matter of "interpreting" what's' known to come up with theories or theologies.
Frankly, I have become relatively annoyed with the Creationists because they tend to put too much time into proving that their interpretive constructions are better than the evolutionists constructions. Humans make mistakes, and it is unwise to take our notions of how the first 10 chapters of Genesis should be interpreted, and treat them as infallible. Genesis is infallible, not my notion of it.
Same goes for the end times. The Bible says that if a strong man knows you're coming, you won't be able to rob his house. So, when talk about the Rapture and the End Times, and we point to this or that and say, "that's it." You can bet the Enemy knows this, too. This leads me to think a lot of the Hal Lindsay stuff I read won't work out the way we think.
Besides, there's a difference between Revelation and Dispensationalism. The former is infallible word of God. The latter is an interpretation thereof, a human construction, and subject to error. And no, I don't know any specifics that I can point to as erroneous. I'm saying here's a theoretical framework that will explain our surprise when a popular end-times scenario plays out unexpectedly.
Trouble is that often things are a little fuzzy, lacking a solid biblical mandate, and we forget that. We affirm those things as if they are gospel. The gospel is infallible, I'm not. I may forget that, or I may well know that things are a little fuzzy, but I don't bother to bog down the conversation with a disclaimer every other sentence.
Now, when you hear someone say something, and it seems a little fuzzy to you, but you think he's stating it as if it is gospel. You owe him the benefit of the doubt. 1) He might know something that you don't, but didn't bother to buttress his case with some factoid he thought obvious. 2) He might not know he's on thin ice. 3) He might know it's a little fuzzy, but he forgot to add a disclaimer. 4) He might know it's fuzzy, but doesn't want to open that can of worms because he wants to make another point. 5) He hasn't learned when to be intentionally ambiguous. In all these cases, you owe him the benefit of the doubt.
The Christian ethic is summarized in the double-love command. Practically, we do that when we give the other the benefit of the doubt. If you find yourself where you can't do that, run away.
When I finally learned how to get an A in philosophy, I discovered something I've found useful ever since. I found that depending upon how I worded the answer on an essay test, I could avoid or open a can of worms full of things I didn't know. There were bits I was certain about and there were bits I were fuzzy about. So, I phrased things that would cover the fuzzy bits. Ambiguity is a good thing to cultivate when you're teasing about the fuzzy bits, but if you know something for certain, you ought to be clear and unambiguous.