With all due respect, I'm not confusing anything even if I was addressing the issue a little obliquely. In both cases ithe hypothesis needs to be proven, not disproven.

This is simply wrong. In science you can only reject a hypothesis. Let me illustrate it via an example. Suppose your theory says that there is a positive relationship between two variables. Your null hypothesis is then that the respective parameter in your statistical analysis is zero. If this very hypothesis is rejected in your test (As you do statistics you are in a stochastic realm so there is always a certain likelihood that your test rejects your hypothesis although it is true. Reporting this likelihood is essential when doing empirical work as it should be as small as possible.) you can claim, loosely speaking, that you have indeed proven that there a non-zero relationship between your two variables. What you formally do is nonetheless to reject a hypothesis and not to prove it.

You're still ignoring decades of research in this. I'm assuming you're ignoring it because it doesn't suit you to accept all those findings against the paranormal. I'm assuming you're ignoring it because you have faith.

Funny how you get called a ghost believer when you point out how the scientific method works. I don't care about this paranormal nonsense and I seriously doubt that any scientist has bothered to spend time with disproving the crap of these people. Do you think you can get tenure via debunking something that is obviously hocuspocus? But hey, like any guy who believes in the power of science I am eager to be proven wrong. So if you list a bunch of papers that deal with "ghost research" I will check them out.

I'm with horatio on this. Hypotheses often cannot be proven, no matter how much data you accumulate supporting them. On the other hand, hypotheses can be disproven fairly easily if they are wrong. To quote Albert Einstein:

This Einstein quote neatly reveals the humility of science. You don't seek something grand like "truth", you seek theories that best fit the facts so far. If a new theory comes along that fits them better or if new facts emerge that stand in conflict with the theory you throw the old theory overboard. If science worked the other way around, via proving hypotheses, it would be far more dogmatic and inflexible.

You have kind of pointed out how the scientific method works (at least certain types of science - not all science is done by hypothesis testing and experimentation), but not entirely correctly. It is true that some science works by disproving a "null hypothesis" - but that doesn't mean that any and every hypothesis proposed is a null hypothesis. One person's hypothesis is that ghosts don't exist. Another person's hypothesis is that ghosts exist. Both hypothesis have been proposed, so which is the null hypothesis? Obviously in the case of ghosts the null hypothesis is that ghosts don't exist. It would be ridiculous to think otherwise because, as others have pointed out, you can never prove the non-existence of something to 100% certainty. Otherwise you're working from the assumption that anything conceivable exists until it is proven that it doesn't. Prove to me that green living bow-ties don't live in the atmosphere of Neptune... What about purple ones? What about Saturn? And so forth (there's an infinite number of possible things I could hypothesize to exist)...

"Working from the assumption that anything conceivable exists until it is proven that it doesn't." I'd slightly change that, anything conceivable could exist. Do you think it was easy for Darwin to conceive evolution in his days or that it was easy for the first guys who came up with quantum theory to get their heads around this funky, highly counterintuitive stuff? As scientist you can theorize about anything. But without any empirical evidence it remains just a theory. As scientist one can check the internal consistency of this very theory, one can even approach it intuitively but one can never claim that it is wrong just because there is no evidence for it. That's what I am trying to say the entire time. Of course I would say anytime that ghosts are made up and do not exist. But if I were a scientist I would have to debunk specific claims by the ghost folks to say that this or that ghost theory is wrong. But I couldn't say that ghosts do not exist just like I could not say that leprechauns do not exist. But I am just an everyman so I can say that leprechauns do exist after the seventh Guinness.

Well, that's basically right. Ghost hunters will propose evidence that they think will disprove the null hypothesis (and thus prove the existence of ghosts). That evidence is assessed and if it is convincing, then scientists would discard the null hypothesis in favor of the existence of ghosts. Until then, it's safe to say that the evidence for the existence of ghosts is not convincing and the simplest solution is to accept the null hypothesis that ghosts do not exist, at least until evidence argues otherwise. Of course, people are free to believe whatever they want (perhaps they have had personal experiences that are convincing), but it's not fair to say that following the scientific method would place the onus on skeptics to disprove the existence of ghosts. If you want an alternative theory, such as the existence of ghosts, to become accepted, you would need good evidence to support it.

Well, I think there are more important things to do than debunking the nonsense of some esoteric folks, e.g. debunking all the corporate-financed propaganda that convinces people that CO2 emissions do not heat up our planet. The humble lesson from this is that our ability to bullsh*t ourselves is far greater than our trust in one of our greatest tools, science.

When rejecting a null hypothesis, it is not really a simple matter of yes or no. You look at the data and statistically determine a probability of the null hypothesis being true. Then you reject it if the probability is below some threshold. Any hypothesis which can be statistically tested in this way can be a null hypothesis. Any which cannot, isn't. You can evaluate a probability that an event would occur without any ghost activity. You cannot evaluate the probability that an event was caused by a ghost.

I think you mostly got it. You do try to reject the null hypothesis. In this case, the null hypothesis is that the ghosts don't exist. The researcher goes out and tries to collect data that rejects the null hypothesis. If you can do that, you then accept the alternative hypothesis, which is that ghosts exist. But, you're not quite correct about the people who come up with "funky hypotheses". Yes, the burden is on them. And, they do in fact look for ways to verify their theories. It is true that you cannot always test hypotheses with current technology. But, they look for ways to test with likely future technology. But, until then, it's just a theory. So, there's a definite burden of proof on them if they want to take it to the next stage. Of course, if enough people get interested in the theory, some one other than the originator may actually prove it. Mr Awe

That's not true of ghost hunting or other paranormal research, such as ESP. They tend to be low budget because there is not a lot of money in that field! For example, ESP research often consists of the subjects guessing the card that someone else picks and then comparing their correct picks to that predicted by randomness. Simple and low budget. Ghost hunting "research" is not scientific. There is no device that detects or measures ghosts. What they do use for ghost hunting is generally cheap off the shelf stuff. But, not rigorous science by any stretch. So, you're statement is objectively false. There has not been a lot of research in this area and it's low budget. Mr Awe

Nope, in science you reject a null hypothesis. Data has to show the null hypothesis is unlikely to be correct. Once you exclude that, you can accept the alternative hypothesis. Mr Awe

True. Having only some experience with a social science where clear empirical results are rare I am slightly theory-biased, valuing theories even if they aren't tested yet.

Well, be careful there. Rejecting the null hypothesis doesn't allow you to accept anything except its exact complement.

It's somewhat-less-than-successful incursions from other universes. When they perfect their methods, we're all in deep shit.

Yeesss, that IS what I'm saying. The alternative hypothesis in statistics is the exact complement. Mr Awe