Is it reasonable to arrive at a conclusion based on lack of evidence to the contrary?

Question

I was having a discussion last night about my atheism, and it was suggested to me that agnostism is the only reasonable conclusion, as it leaves the door open for new information.

This made me think, were they right? Or is a total lack of evidence for a contrary position justification for a logical conclusion?

Answer 1

The dichotomy you state between agnosticism and atheism is false. This is perhaps one of the most misunderstood terms of the 21st century. You can be an agnostic atheist and an agnostic theist. In general, the split between agnostic vs. gnostic theists is more in the middle (closer to 50/50), whereas most atheists are agnostic atheists (there's just no way to prove for certain that God (or anything) definitely doesn't exist).

Answer 2

The lack of evidence for a contrary position is only justification for a conclusion if there is a good reason to expect that there would be evidence if the position were true. For example, there may not be any specific evidence that bigfoot does not exist. But one can make a case that if there were such creatures, someone would have found them by now.

I have a friend who likes to watch Ghost Hunters. My joke to her whenever she mentions an episode of the show is, "Isn't that the episode where they finally proof of the existence of the paranormal?"

Agnosticism actually is the position that closes the door to new information. A theist may be open to disbelief if he is exposed to contrary evidence. An atheist may be open to belief if he sees evidence of god. Agnosticism is the position that no sufficient evidence of either god's existence or his non-existence is possible. That is, agnostics hold that the truth of god's existence or nonexistence is unknowable to humans. Agnosticism is the position that one cannot ever know that god exists nor can one ever know that god does not exist.

I think you're confusing agnosticism with weak (or critical) atheism. Weak atheism is a refusal to believe in a god due to a lack of evidence without claiming that one knows that no god exists. Atheism and theism are the two alternate positions on belief in god -- one can believe or one can not believe. Agnosticism is a position on the knowability of god's existence. (There are people who claim to hold positions that are neither theistic nor atheistic, but that's a different kettle of fish.)

[A]gnosticism is the view that human reason is incapable of providing sufficient rational grounds to justify either the belief that God exists or the belief that God does not exist. In so far as one holds that our beliefs are rational only if they are sufficiently supported by human reason, the person who accepts the philosophical position of agnosticism will hold that neither the belief that God exists nor the belief that God does not exist is rational. -- Routledge encyclopedia of philosophy

Answer 3

Is it reasonable to arrive at a conclusion based on lack of evidence to the contrary?

Of course it is; we do it all the time. Most of us have concluded that the moon is not made of green cheese because there is no evidence to the contrary.

We have a near-infinite number of hypotheses that face us daily, and we make judgments based upon the evidence, for and against, we have available. None of this adds up to certainty (in a philosophical sense), but from a pragmatic standpoint we usually have all of the certainty we need.

Answer 4

Or is a total lack of evidence for a contrary position justification for a logical conclusion?

Not to be dismissive of very real and interesting epistemological questions about warrant, justification, and the like I would contend that when their is truly no evidence (that one knows of) in favor of a certain position it is simply not possible to "believe" it. One may want it to be true, or want it to be false. One may probably even be able to have some judgment on the theoretical possibility that evidence will be forthcoming, though more often than not this may be heavily influenced by hope.

Similarly, one may not realize that there is not evidence for a position one believes in, but by the act of believing in the position one is implicitly [mistakenly] believing that there is basis for believing it. Such a belief is based on assumed evidence, which cannot be the case when one knows their isn't any evidence. Similarly people may base beliefs off of mistaken evidence, but not evidence they know is mistaken. Of course we are probably getting close to the point whether my opinion on this matter can be tested empirically and I certainly feel it would be worthwhile research.

Regarding the substance of the dispute however I would not concede that there is a total lack of evidence but I'm quite certain that's its own discussion.

Answer 5

Do you put garlic around your windows every night, just in case there are vampires lurking? Do you put milk out for the potential fairies at the bottom of your garden as well? There are millions of other hypothetical mythical beings we dismiss although we can't absolutely "prove the negative" of their non-existence with logical certitude (apart from the self-contradictions in many mythological concepts).

If we should have expected to see evidence for something by now but have not, then we should conclude it probably doesn't exist. If possible evidence is rare but may occur in the future, we should consider it possible but not yet demonstrated. If there is no evidence and it will not be possible to find evidence for it in the future than it should be considered meaningless and not believable. So yes, lack of evidence can lead you to a robust conclusion.

As an empiricist concepts are valuable to me if they help make sense of the world, and meaningless or unsupported concepts are damaging as they take up my limited brainpower and time which could be used more productively. In real life we never have 100% (dis)proof of anything, but that should not stop us removing generally useless or misleading ideas from our mental toolkit.

The distinction between gnosticism and agnosticism is a false dichotomy as complete knowledge or certainty doesn't exist outside axiomatic systems and there is almost always some evidence for or against a belief. The appropriate judgment is whether you have sufficient confidence in your conclusions that they inform your everyday decisions. For example I have no more belief in supernatural entities than in the possibility that a black hole is hiding in my kettle and will swallow me up when I next go to make a cup of tea, and act accordingly. In practice sufficiently unlikely possibilities must be ignored.

Of course I could change my mind given new evidence. If the stars in the sky rearranged themselves to spell out "Ragnarok is coming next Thursday" in Old Norse I would reevaluate my beliefs about Odin (after checking I was not hallucinating). However that possibility does not mean I am a semi-theistic agnostic with the currently available evidence.

Answer 6

Yes, it is reasonable to infer X on lack of evidence for not X, under specific contexts but not in general.

Suppose you see a hundred crows, all of which are black. You would be reasonable to infer that all crows are black (maybe even going so far as to define a crow to be black, including it in the defining characteristics). This works in the bayesian statistical inference method. But that is no guarantee that absolutely no crow will appear that is not black.

This is related the hypothesis about the closedness of the set of data under consideration. One can assume the Closed Word Hypothesis, which means, in the set of data at hand, if A does not appear, you are allowed to infer (or really, you know) that -A is true (or -A must appear). The Open World Hypothesis says that you only know of things stated not about unstated things (but then Bayesian methods apply, you get more and more confident that -A is true the more times you do not see A).

It is a classic blunder of Hegel's (sorry, a classic myth about Hegel) that he said that there could be no more than seven planets, and in the same year as this proclamation, another planet was discovered. (It's so much more complex than that: the 'planet' was Ceres, Hegel 'proved' that Bodes Law was not correct not that there were no planets beyond Saturn, but the asteroid belt (which Ceres is a part of) fulfills the numbers of Bode's Law.)

But anyway, there are some negatives you can prove and some you can't. You can prove that there are no primes that are both even and greater than 2. You can't prove (experientially) that there an X (with consistent properties) doesn't exist in an unexplored area.

Then again, here is the classic informal disagreement between Russell and Wittgenstein, where Wittgenstein claimed that there is no evidence that there is not a rhinoceros in the room, and Russell took a more practical tack.

Answer 7

Is it reasonable to arrive at a conclusion based on lack of evidence to the contrary?

Yes, especially if there are no rational and compelling reasons whatsoever to assume that what is lacking is evidence.

For example, somebody tells you to sit at a table and knock 16 times, then a ghost will appear. Do you try it? Maybe. It turns out it doesn't work. The next day the same person tells you it was his fault because you must knock 17 times. And so on.

This shows that we just do not have enough time to think about, let alone disproof every silly possible hypothesis. If someone claims something, then he also has the burden of proof. That's about it.

Answer 8

I am a strong agnostic. I am not an atheist because first, I do not believe that a negative can be proved, and second, I believe that in this unexplored universe or some other, there is a tiny possibility that a diety is running around somewhere. When I see the atheist "flying spaghetti monster" argument, I simply acknowledge that I have no way of disproving his existence either. At our current state of development, definitively believing that there is no deity at any time or any place anywhere fails for lack of evidence, as does the opposing view. We have yet to explore 99.999% or more of the known universe, and no other universes within the postulated metaverse, so it is premature to draw any theistic or atheistic conclusions through inductive or deductive reasoning. The search is in it's embryonic stage. So often I find myself told that I am "in between" which I think you have done a wonderful job of debunking. So for the moment I am back to searching for a god or at least a superior life form. Since I am not an astronomer, I so far have been limited to looking behind the couch and under the bed. No luck so far, but I have a long way to go to attach myself to one side or the other.

Answer 9

I was having a discussion last night about my atheism, and it was suggested to me that agnostism is the only reasonable conclusion, as it leaves the door open for new information.

Why would "leaving the door open to new information" Make any view on religion(s) or world views seem more or less reasonable (Which I assume just means true) Again whether some position is open to new information and whether it is true or not is not a related question.

Even if a certain world view is not open to new information it can certainly still be true. The inverse is also true. It is also entirely possible for a world view to be open to new information and still be false.

The person you talked with seems to confuse the issues.

This made me think, were they right? Or is a total lack of evidence for a contrary position justification for a logical conclusion?

Though it true that their is the maxim that lack of evidence is not in itself evidence for a positions falsity I would like to add that the more apt conclusion in such a case would be...

1) to either assert that the evidence is insufficient to make a conclusion and hope that more evidence arrives at a later date.

OR

2) Decide that the method that you where you are using is inadequate to investigate the proposition and propose a better one (If such a thing exists).