You won't be surprised to learn that what these terms mean is a matter of some controversy among scholars. Some bits, however, have achieved general agreement. Pyrrhonian and Academic skepticism mark two branches of ancient skepticism. David Hume and other moderns also used the terms. One way to discriminate them is institutionally. Not long after Plato's death his school just outside of Athens, the Academy, became dominated by skeptical thinkers. The philosophical work engaged by those thinkers came, of course, to be called Academic skepticism. The major texts by which Academic skepticism, however, came to be known to the modern world were not those of philosophers leading the Academy but, rather, of the Roman philosopher, Cicero. His books, Academica and De natura deorum, became highly influential. Pyrrhonian skepticism, by contrast, follows a line rooted in the thought of a man named Pyrrho, who lived in small town of Elis, on the other side of Greece. Pyrrho was not associated with a prominent institution and seems to have written nothing. His follower, Timon, however, did make it to Athens and wrote a book called the Silloi or Lampoons. Centuries later, Pyrrhonian skepticism, became associated with the work of Sextus Empiricus. His book, Outlines of Pyrrhonism, was the single most important conduit of Pyrrhonian ideas into today's philosophical world. And it's probably the ideas in which you're most interested. In general, Pyrrhonian skepticism is taken to be more radical than Academic skepticism. Pyrrhonism is associated with ideas like: the suspension of all belief, a rejection of all knowledge claims and all criteria for distinguishing truth from falsehood. Academicism is associated, instead, with the abandonment of absolute certainty and definite knowledge, in particular the rejection of the Stoics' ideas about indubitable perceptions. But Academics are held to accept the more moderate position of probablistic belief and probablistic criteria. By this I mean Academical skepticism is thought to reject claims to definitely know X but not the idea that some beliefs about X are more probably true than others. For myself, I think this isn't the best way to distinguish the too schools. I think that Pyrrhonians and Academics actually shared a great deal in their views about knowledge and truth. Academics, however, were more willing to construct philosophical theories and to engage in philosophical debates with other philosophical schools. Central among those Academic theories are certain decision procedures for belief, procedures that might still be consistent with the abandonment of criteria for knowledge and truth. Pyrrhonians, by contrast, for fear of becoming themselves dogmatic, developed little philosophical theory of their own and spent most of their time deconstructing philosophical dogma per se. Pyrrhonians did, however, embrace in a non-dogmatic way what they saw as "common life" and in particular the fourfold guidance of (1) the practical technologies of life, (2) nature, (3) the compulsion of our feelings, (4) the customary practices of the societies in which they find themselves.

You exist right now, right? You have some specific number of hairs on your head, and your toenails are some definite shape, etc. Nobody's keeping track of any of these things, though. Now flash forward to the year 3000, when you've completely and totally faded into obscurity. There is no possibility whatever of retrieving any information about you. Did you every exist, with your specific attributes? I suspect you're going to say "of course." Ditto for all the people who preceded you. To be is not to be remembered!

Thank you for your question. I would suggest that the "secondhand" opinions you are interested in might in some cases be justified; in others less so. Imagine for instance that I've read a good deal about environmental damage in China. I've never been there, and so have no firsthand experience of the situation, but I have read reputable sources of various kinds on the issue, and have done so at some length, making a point of seeking out different positions on the issue. In a case like this, I would suggest, it is acceptable for me to form an opinion on the issue in spite of having no firsthand knowledge.

By contrast, and all too often, people form secondhand opinions about issues on which they have done inadequate research. One only needs to listen for a few minutes to talk radio shows of various kinds, for instance, or user comments on online news sources, to see how many people form confident opinions on important issues (terrorism, economics, war, etc.) about which they are woefully ill-informed.

I would suggest that the issue here is not being firsthand or secondhand. Rather, I would suggest the issue is how well informed the person is who forms the opinion. Of course, even someone with firsthand knowledge of a situation can form an ill-considered opinion about it. (Think of someone who sees one person using food stamps at a grocery store to buy junk food, and then concludes that food stamps are always abused and should be banned.)

I would also suggest that in the case of authors, we tend to look down on people who make judgments without reading their books, because it seems rather lazy not to bother to do so. After, reading someone's book is a good deal easier than getting oneself to China! Again, about historical events, you're right to suggest that we can do no better than have secondhand knowledge. Whether or not we can *always* do without firsthand knowledge is a more controversial issue. I'd suggest, however, that again the issue is not so much whether our opinion is firsthand or not, but rather how well researched it is. If that's right, then so long as we do our "homework" on an issue, we can form justified opinions without needing firsthand knowledge. Obviously, exceptions include cases like knowing what a thing looks like, tastes like, sounds like and so on: In these cases there is no substitute for "being there."

Mitch Green

It clearly would be betrayal since Bob is regularly doing something he tells his wife he is not doing, and deception is part of betrayal. She does not know but to argue that as a result she is not harmed is like arguing that if I steal from someone and they never know, then I am not harming that person. Clearly I am and theft is not only theft when the owner of the stolen property misses it.

Perhaps even more significant here though is not the harm to Mary but the harm to Bob. He apparently spends a year lying to someone, and carrying out the activity which he denied practising on perhaps a daily basis, and one wonders what effects this has on his character. Would this make him likelier in the future to be tempted to deceive others? Might this encourage in him a feeling of contempt for the truth and communicating the truth to others, even those close to him? These factors suggest that there is also an issue in whether Bob is in danger of betraying himself as well as Mary.

There are a couple of ways we might think about the questions you're raising. One is by trying to look for an Archimedean Point, so to speak, that provides some sort of absolute or incontrovertible answer. The other way is to look at how we actually think about these sort of things -- look from the inside. Since I have no Archimedean point available to me, I'll offer the latter sort of response.

What we think does depend on what we've experienced, but even though my life is different from yours, we have lots of common ground to appeal to. Obvious sort of case: if you and I were both to look out my office window, then even though your experience is not just like mine, we'd agree that there's a building directly across from us. We'd also agree that there's a large grassy area behind it, and that there are people wandering around in the vicinity. Other cases of ho-hum agreement among people are more complicated, but we could multiply examples indefinitely.

We can also agree that some people are better positioned to have a view. If I look at an x-ray, my opinion about what I see isn't worth much. I know that, and so does anyone who knows that I have no medical training. But a radiologist can tell a lot. I'll defer to her opinion, and so should any sensible person in my position.

And on it goes. Our ordinary notions of evidence, reasoning and so on clearly can carry us a long way. Add the refinements of science and math and we get even further. By those lights, some people really are more justified in believing certain things than others, and we can come to reasonable consensus about who is who. Some of what "led you to being who you are today" was sound: soaking up the deliverances of your senses, thinking carefully about evidence, taking counsel from those who know more than you.

Two things, however. One is internal to the whole system. There are hard cases, and there may even be unresolvable cases -- from the point of view of our usual conceptions of evidence and reasoning. True though that may be, however, it doesn't undermine the fact that we know a lot, and that not everyone is equally expert on everything.

The other point may be closer to your worry. We could toss everything up in the air and become skeptics about all our usual beliefs and standards. We could do that, but the mere fact that it's possible doesn't give us much of a reason to. There's a larger point here. We can look at knowledge, belief, expertise, etc. notions that call for the sort of Archimedean perspective that we noted above and duly set aside. Some philosophers think that unless we can find such a point (and we can't), then skepticism is the only reasonable response. Most philosophers, for better or worse, think that that's a hopeless approach.

So in short: from the point of view of our usual standards and practices, we have all sorts of reasons to think that some opinions are better than others. If we toss all those standards and practices aside, we're radically adrift. But there's no compelling reason to give ourselves over to the currents.

It isn't right to say that Christianity, per se, advocates a god that values what you might call blind faith, i.e. faith which is not grounded in reasoned argument. Perhaps that's true of some sects, but certainly not all. Catholic tradition has it that the existence of God is rationally demonstrable (and that God wants us to use the reason that we have been endowed with). So those atheist critics who argue that the supposed arguments for God don't work -- whether purely a priori arguments or partially empirically based arguments -- aren't point-missing, but are directly engaging with a major strand of Christian thought which holds that there are rationally compelling arguments for his existence.

But suppose you do posit some god that goes out of its way to hide itself and give no rational evidence for its existence (even though it wants us to be credulous and believe in it). Then to be sure, the empirical state of the world is the same whether or not such a being exist. By hypothesis, we have no evidence, empirical or otherwise, that such a god exists. But then why on earth believe in it any more than in all the little green demons or the Flying Spaghetti Monster that equally hide themselves away? By hypothesis, there isn't the foggiest reason to believe in such things. So don't.

Initial disclaimer: I am no epistemologist. But I'm not sure I quite understand. First, why are all assumptions about basic beliefs, etc. dogmatic? Are you perhaps demanding that one must be certain of such things? Why isn't it good enough to say "I know Peter was at the meeting because I was there and I spoke with him?" People who say things like that could be mistaken, of course. But suppose that as the world turns out, I'm right: I did attend the meeting and I did speak with Peter. Then don't I know that he was there? If not, why not?

Perhaps the worry is that I don't know that I know this (doubtful in this case, but happens sometimes.) But it's long been doubted that knowing X requires knowing that you know X. Perhaps the thought is that to know X always requires being able to give some particular sort of justification. But reliabilists wouldn't buy that. On their view, I know something (roughly) if my beliefs about it come to be in a reliable way, even if I have no clue what the mechanism is.

So while certain sorts of projects in epistemology fail, the field is still thriving, near as I can tell. But in any case, it seems to me that one sensible version of the epistemological enterprise takes it for granted: we know lots and lots of stuff. The project isn't to prove this, but to provide plausible analyses and accounts of what this amounts to. Seems like a reasonable project to me.

If you want to try something rather more accessible than the heavy-duty books that Eric Silverman suggests, then try Richard Dawkins The God Delusion. Sure, it's shallow in places, and a bit crass in others, but it will certainly be an enjoyable read that gets you thinking hard.

You say: "if I stop thinking I'll, well, die"? This calls to mind that very famous idea from Descartes, "I think, therefore I am." What he means is that as long as I'm thinking, I must exist. What seems to worry you is the opposite--"If I don't think, I won't exist." But here's a very reassuring thing about Descartes' view. It doesn't matter what you think about. You can think about the existence of God or going swimming or eating ice cream, and the fact that you are thinking means you exist. In fact, what Descartes means by thinking is everything that goes on in your mind. So you can just enjoy the swimming and the ice cream, and that suffices for you to exist. In a relevant sense we even keep thinking in our sleep. Our minds are active. So closing your eyes at the end of the day isn't even anything to worry about.

Of course, some things urgently need to be thought about. And maybe it seems to you as though the question of God is really urgent. But is that so? If there is an all-good supreme being, I don't think it makes sense to think of him as punishing you for being an atheist or an agnostic, or rewarding you for being a theist. In each case, you come by your beliefs honestly, so what's to punish or reward? There's no reason to think your welfare turns on getting this sorted out. All the more reason to let yourself think about swimming and ice cream...and about religion only as much as you enjoy doing so.

I have a couple of comments.

First, let me commend you for your sincere interest in an important topic.

Second, beliefs that you are "scared into" are unlikely to last long-term. You are wise to be skeptical of such a process.

Third, you don't need to 'stop thinking', but your mom is correct that you should relax. This is not an issue that you are likely to get a quick resolution on.

Fourth, now for the really bad news. There is nothing resembling a consensus among philosophers on this issue. Many have thought God exists and it can be proven. Others have thought that the evidence is inconclusive, but that we should believe in God for either moral reasons (Immanuel Kant) or for prudential reasons (Blaise Pascal). Still others have thought that the evidence was inconclusive, so that we shouldn't believe. Yet, others have thought there was weight of evidence against belief in God. And finally, others have thought that all claims about God were inherently absurd.

I'd encourage you to take things slowly and talk to your friends, family, and religious leaders on the topic. You don't need to come to a final decision on one of the great philosophical debates at the age of 13. Eventually, I'd encourage you to read some great philosophers on this topic including Hume's Dialogues Concerning Natural Religion & Mackie's the Miracle of Theism (both against belief in God) and Richard Swinburne's The Existence of God & There is a God by Anthony Flew (both in favor of belief). However, I find most popular treatments of the issue to be pretty shallow.

For my part, I find that probabilistic versions of Aquinas's second argument for God's existence and Leibniz's cosmological argument are fairly convincing in favor of belief (both of which can be found via a google search).

I hope this helps.