... Perhaps for clarity I should have prefixed every term with "I have looked under my bed for evidence of tigers, and ... "
I think you have misunderstood what I am saying. (It's quite possible I am misunderstanding what you are trying to say, as well.)
There are two points I am trying to make. They are:
(1.)
Lack of belief and
disbelief are not the same.
(2.) There are times when disbelief is reasonable, but there are also times when
lack of belief is reasonable and
disbelief is unreasonable.
The first point, whether lack of belief and disbelief are the same, is what I thought you were trying to demonstrate with your tiger example. If so, I believe there is a crucial error in your logic. What you have demonstrated is that it is possible to create
an example where lack of belief and disbelief are the same. But the point in dispute is not whether the two
can be the same -- it is whether they
must be the same. So what matters is not whether an example can be constructed where they
are the same but whether an example can be constructed where they
are not the same. I believe I have done so in the example I presented. You do not need to defend your example; you need to show the flaw in mine.
The reason why your tiger example works as a case where, for a reasonable person,
lack of belief and
disbelief are equivalent, is (a) because the chances of a tiger being under the bed are extremely small, and (b) if there were one under the bed it would be fairly easy to detect. Therefore it is possible to look under and be reasonably clear that there is no tiger there. In this case, lack of evidence gives clear cause not only for
lack of belief (the default position for a reasonable person when sufficient evidence for belief is lacking) but for
disbelief as well.
But in everyday life, this is frequently not the case. With small everyday objects, such as a toothbrush -- or a ring, or keys, or a slip of paper -- it is quite possible they have migrated under the bed, and quite possible that merely looking under the bed will not detect them. They might, for example, be underneath or behind another object. While simply looking under the bed is adequate to dispose of the tiger-under-the bed possibility, an actual search is required to dispose of the toothbrush-under-the-bed possibility -- and that may require crawling under the bed, or moving the bed. Given that this will be inconvenient, and given that there may be other places which are more likely to hold the missing object and which are easier to search, searching under the bed may not be a top priority. And until that careful search is carried out, it is reasonable to
lack belief that the missing object is under the bed, but it is unreasonable to
disbelieve that the missing object is under the bed.
This kind of situation comes up fairly frequently in life. Very often, and for a wide variety of reasons, it simply is not possible to carry out good tests. And even in the cases where it is possible to carry out tests, there is a period of time
before those tests are carried out. It is during that period when
lack of belief and
disbelief are most likely to be distinctly different -- and when it is most important for skeptics, if we are ever to gain wider acceptance by the public at large, to appreciate and respect that difference.
The person who
disbelieves simply because there is not evidence to
believe is not practicing skepticism. It is as non-skeptical to disbelieve without adequate grounds as it is to believe without adequate grounds. Unfortunately, that is the view that much of the public holds -- that skeptics are people who are
antagonistic to unproven things.
For example: in the 1950s the Soviets launched satellites into space. In 1961 they claimed to have put a man into space. This was an extraordinary claim, requiring extraordinary evidence. And, over time, this evidence was forthcoming. But in the initial days, it would have been quite reasonable for a person to take a wait-and-see attitude -- to withhold belief (i.e. to
lack belief) until the evidence was in.
It would not, however, have been reasonable to disbelieve -- to claim that the Soviet claim was a hoax. Disbelief is itself a claim (that the claim being made is false) and requires supporting evidence.
The question of intelligent life on other planets is another example. As yet, we have no evidence that there is intelligent life on planets other than earth, and it is unlikely we will be able to carry out tests on planets outside our solar system any time soon. A default position of
lack of belief is reasonable; a position of blind
disbelief, on the other hand, is as unreasonable here as a position of blind
belief.
Global climate change is third example. Some people feel we do not yet have enough data to establish whether climate change is occurring, whether human activity is a significant contributing factor, whether the change (if it is real) poses any significant threat to human life and well-being, and (if so) whether there are feasible measures which could be taken to reverse or lessen those harmful effects. If someone feels the data is inconclusive, a default position of
lack of belief (
I am not yet convinced that global climate change is real / is human caused / is a significant problem) is reasonable. A position of (
disbelief (
Global warming is a fraud, and those who believe in it are liars or idiots) is not; it is a separate claim, requiring separate evidence.
The difference between
lack of belief and
disbelief is real, and there are numerous matters where this difference is significant. That is the point I am making. What point are you making, and how are we in disagreement?
