There seems to be nothing incoherent in the idea that there might be certain people who are much more reliable about the future than the rest of us, though neither we nor they can account for the source of this extraordinary talent. I don't think it is likely that there are any such people about; but if there are this might have an entirely natural explanation (even if we can't quite figure it out). Perhaps they are much more sensitive to sensory evidence and its significance than the rest of us.
It seems to me that you're asking whether there's a general rule of inquiry that one could adopt that will lead to the truth. I presume the answer is No. Inquiry requires judgment, taste if you will, and that has resisted all attempts at reduction to a collection of rules that can be mechanically followed.
Your question reminds me a little of the story Bertrand Russell told about the philosopher who claimed that solipsism -- the view that only you exist or anyway that there is no reason to believe anyone else exists -- was obviously the correct position and she couldn't understand why everyone else didn't agree with her! But there does seem to be a sense in which you cannot prove that anyone other than you exists. Actually, in that sense, it also seems that you can't prove that you existed in the past or will exist in the future. So you if you have standards this high, then the most you know is the content of your current experience, though even this may be saying too much.
Fair enough, Alan. Based on my experience of human beings, the more sociableand cheerful attitude that you suggest seems appropriate as ageneral day-to-day attitude toward others. I’m generally not worriedthat people are lying to me.
But I understood the question differently– not as directed to humanity in general, but at usin particular, the panelists on AskPhilosophers. I took the questionernot to be wondering whether we were lying but whether we knew what wewere talking about. There are a lot of people out there promisinganswers to life’s big questions, and skepticism seems to me to be aperfectly healthy response to these promises. It was for this reasonthat I tried to assure the questioner that we aren’t making any suchpromises.
There seems to be a pattern of argument here that needs to be questioned. It is: (i) Method M for reaching judgements isn't completely reliable; therefore, (ii) method M can't be trusted. The conclusion simply doesn't follow. Method M might be very reliable, in which case it can be trusted to a high degree.
I doubt "group opinion" is the only method available to us for distinguishing hallucination and illusion from perception. (For example, in the land of the blind, there might be ways of correlating your apparent perceptions with facts on which you can all agree, e.g., that there is a boulder in such-and-such a location that wasn't there yesterday.) But it might be quite a good way of drawing the distinction even if it isn't a perfect way.
On one view of time, the future is as real now as the present or the past, much as other places are as real as the place you happen to be; on another view the future is not yet real but will be. Either way, many philosophers would say that we can know some things about it, though Hume's great sceptical argument against induction attacks this idea. But Hume's argument is not especially about the future: it applies to any inference from what we have observed to what we have not observed, whether what we have not observed is in the future, present or past. In any event, it's not very surprising that we believe we can know something about the future, since we have so often formed expectations that we have subsequently found to be satisfied.
I assume your worry is not about whether you are untrustworthy in some areas, or in some sorts of enterprises. As Peter Lipton says, if you are dishonest as a general rule, then plainly you can know that about yourself. And all of us have excellent reason to think that we are not good at many things.
But if your question is whether you could have any good grounds for thinking that you are untrustworthy in some very general way (for example, epistemically--in the way you generate beliefs about the world), then I think the answer is also yes. Most skeptical arguments seem to me to give at least some reason for thinking that we are epistemically untrustworthy. Most philosophers these days are not won over by skeptical concerns, but that is not to say that they regard such concerns as logically impossible or incoherent. I think, moreover, that the field of moral psychology gives us some reasons for thinking that we may be somewhat untrustworthy in other areas, as well.