God and the Absence of Evidence Argument

[Sunstone]

PLEASE NOTE WELL: This thread is about the logic of arguing that a god does not exist based on the absence of any evidence for that god's existence. This thread is NOT about whether there is or is not evidence for the existence of a god. All posts that attempt to assert evidence for the existence of god will be considered off topic and ruthlessly deleted faster than a seventeen year old virgin can shed his or her pants on prom night.​

For the purposes of this thread, please begin by assuming that there is neither sufficient nor conclusive evidence for the existence of a god. The essential question then is whether or not the lack of sufficient and/or conclusive evidence for the existence of a god provides us with sufficient and/or conclusive evidence that a god does not exist?

Or more simply, if there is no evidence for a god, does that mean there is no god?

On the surface, we might quickly answer "no". That is, we might say that the lack of evidence does not mean there is no god. After all, is not Martin Rees' aphorism correct: "Absence of evidence is not evidence of absence"?

But what about cases in which a lack of evidence for something does indeed suggest that something does not exist or is not present? For instance: Suppose your doctor tests you for cancer. No cancer is found. Isn't that evidence that there actually is no cancer?

Or, as the logician Irving Copi once wrote, "In some circumstances it can be safely assumed that if a certain event had occurred, evidence of it could be discovered by qualified investigators. In such circumstances it is perfectly reasonable to take the absence of proof of its occurrence as positive proof of its non-occurrence."

Can we assume that, if a god existed, evidence for that god could be discovered by "qualified investigators"?

If we answer "yes" to that question, then why yes? And if we answer "no" to that question, then why no?

 

[exchemist]

PLEASE NOTE WELL: This thread is about the logic of arguing that a god does not exist based on the absence of any evidence for that god's existence. This thread is NOT about whether there is or is not evidence for the existence of a god. All posts that attempt to assert evidence for the existence of god will be considered off topic and ruthlessly deleted faster than a seventeen year old virgin can shed his or her pants on prom night.​

For the purposes of this thread, please begin by assuming that there is neither sufficient nor conclusive evidence for the existence of a god. The essential question then is whether or not the lack of sufficient and/or conclusive evidence for the existence of a god provides us with sufficient and/or conclusive evidence that a god does not exist?

Or more simply, if there is no evidence for a god, does that mean there is no god?

On the surface, we might quickly answer "no". That is, we might say that the lack of evidence does not mean there is no god. After all, is not Martin Rees' aphorism correct: "Absence of evidence is not evidence of absence"?

But what about cases in which a lack of evidence for something does indeed suggest that something does not exist or is not present? For instance: Suppose your doctor tests you for cancer. No cancer is found. Isn't that evidence that there actually is no cancer?

Or, as the logician Irving Copi once wrote, "In some circumstances it can be safely assumed that if a certain event had occurred, evidence of it could be discovered by qualified investigators. In such circumstances it is perfectly reasonable to take the absence of proof of its occurrence as positive proof of its non-occurrence."

Can we assume that, if a god existed, evidence for that god could be discovered by "qualified investigators"?

If we answer "yes" to that question, then why yes? And if we answer "no" to that question, then why no?

I agree.

I have always maintained Martin Rees* erred when he said that. What he should have said is that absence of evidence is not proof of absence.

It seems obvious that absence of evidence for fairies at the bottom of my garden is, when accumulated over a sufficiently long period of time, evidence that there are, most likely, no fairies there.

So absence of evidence most certainly can be evidence of absence - just not definitively so.


* In fact I had no idea, until you said so and I checked it, that it was Martin Rees who said this. I had always thought it nonsense and I am quite surprised to find it was him.

 

[lewisnotmiller]

No.
There are limits to what we can scientifically test for. Using your cancer example, we know what cancer looks like and how to find it. However, this was not always the case.

So in ancient Rome, a test for cancer is not possible. Today, we are surely limited in our ability to identify everything, despite the boundaries of those limits being ever pushed back.

Therefore logically I must allow for the existence of things beyond that boundary. It is possible that a God who does not interact with this world sits beyond the boundary of our current science.

I'll avoid talking about the implication of that here to respect your wishes re: tangents to the OP, but am happy to extrapolate here or elsewhere if you wish.

 

[Sunstone]

I agree.

I have always maintained Martin Rees* erred when he said that. What he should have said is that absence of evidence is not proof of absence.

It seems obvious that absence of evidence for fairies at the bottom of my garden is, when accumulated over a sufficiently long period of time, evidence that there are, most likely, no fairies there.

So absence of evidence most certainly can be evidence of absence - just not definitively so.

What if we have good reason to believe there are no "qualified investigators" when it comes to fairies? Can we still say absence of evidence for fairies can be evidence of absence?

Please note: I am neither asserting there are or there are not qualified investigators. I am merely asking as a hypothetical, what if we had good reason to believe there were none?

 

[exchemist]

What if we have good reason to believe there are no "qualified investigators" when it comes to fairies? Can we still say absence of evidence for fairies can be evidence of absence?

Please note: I am neither asserting there are or there are not qualified investigators. I am merely asking as a hypothetical, what if we had good reason to believe there were none?

I think "qualified investigators" is a red herring, as far as the general principle goes that absence of evidence can be evidence of absence.

You only need to invoke "qualified investigators" in specific cases in which the presence or absence of evidence cannot readily be determined by the man on the Clapham omnibus. (I live in Clapham by the way.)

 

[HonestJoe]

There’s a distinction between definitively proving something and a practical assessment of its likelihood. I do think that we can’t prove (or disprove) anything entirely 100%. However certain we might be about a simple fact, it is possible, however unlikely, that we’re mistake or are being misled. After all, there is the whole question that we could be in some kind of artificial reality and so literally nothing we think as being real actually is. That way can only lead to insanity though. In practice we have to rely on the most likely truth based on our limited perception, with an element of balancing the risk of us being wrong.

The other aspect is whether it even matters. The question of whether some kind of god exists or not doesn’t. Working on the basis of some god existing wouldn’t actually look any different to working on the basis that no gods exist. Practical implications only come in to it once you get in to specifics, all the purported rules, law and sins with the related promises and threats associated with them. That’s where you get in to things like (the flawed) Pascal’s Wager and the like. In my opinion the fact there are so many claims, often contradicting both each other and other established facts, it makes no sense to accept any one without sufficient evidence to prove any.

“I don’t know” remains a perfectly valid answer to any question.

 

[Sunstone]

I think "qualified investigators" is a red herring, as far as the general principle goes that absence of evidence can be evidence of absence.

You only need to invoke "qualified investigators" in specific cases in which the presence or absence of evidence cannot readily be determined by the man on the Clapham omnibus. (I live in Clapham by the way.)

What makes you certain that evidence for the existence of a god -- if there was such evidence -- would be readily available to the man on the Clapham ominbus, and not require any special qualifications to discern it? Just curious what your reasoning is.

 

[Sunstone]

The other aspect is whether it even matters. The question of whether some kind of god exists or not doesn’t. Working on the basis of some god existing wouldn’t actually look any different to working on the basis that no gods exist. Practical implications only come in to it once you get in to specifics, all the purported rules, law and sins with the related promises and threats associated with them. That’s where you get in to things like (the flawed) Pascal’s Wager and the like. In my opinion the fact there are so many claims, often contradicting both each other and other established facts, it makes no sense to accept any one without sufficient evidence to prove any.

“I don’t know” remains a perfectly valid answer to any question.

What does any of that have to do with the OP?

 

[LuisDantas]

Can we assume that, if a god existed, evidence for that god could be discovered by "qualified investigators"?

For the purposes of personal stance, we sure can, and arguably we may have to.

That is why atheism is a valid stance as opposed to some form of abuse or fallacy.

Things are very different however if we are dealing with attempts at arguments for discussion of the matter with other people.

If we answer "yes" to that question, then why yes? And if we answer "no" to that question, then why no?

"Yes" for personal purposes. Because it is ultimately our personal call whether we believe in a deity's existence or not.

"No" for arguing, because it is conceivable that a deity would choose to leave no evidence of its own existence. That would arguably make it irrelevant, or even unworthy of consideration. But it is impossible to establish logically that there is no deity whatsoever, exactly because it is not clear that deities would be detectable or at all relevant.

 

[Sunstone]

No.
There are limits to what we can scientifically test for. Using your cancer example, we know what cancer looks like and how to find it. However, this was not always the case.

So in ancient Rome, a test for cancer is not possible. Today, we are surely limited in our ability to identify everything, despite the boundaries of those limits being ever pushed back.

Therefore logically I must allow for the existence of things beyond that boundary. It is possible that a God who does not interact with this world sits beyond the boundary of our current science.

Good points. I agree with you that we cannot know what the sciences will or won't turn up in the future -- especially the distant future.

 

[savagewind]

Suppose your doctor tests you for cancer. No cancer is found. Isn't that evidence that there actually is no cancer?​

No! It's called a false negative, I think.​

Can we assume that, if a god existed, evidence for that god could be discovered by "qualified investigators"?

Yes but, I think those do not exist on Earth and I don't know why.

 

[Augustus]

I have always maintained Martin Rees* erred when he said that. What he should have said is that absence of evidence is not proof of absence.

It seems obvious that absence of evidence for fairies at the bottom of my garden is, when accumulated over a sufficiently long period of time, evidence that there are, most likely, no fairies there.

So absence of evidence most certainly can be evidence of absence - just not definitively so.

If you treat it as an aphorism expressing a general truth rather than a definitive statement of fact then it is ok. I would guess that's the way it is intended.

 

[Jumi]

Assuming we are talking about scientific evidence...

Without evidence to the contrary the doctor says you're cancer free, yet there is a percentage that you have cancer. In case of cancers, we have some idea what that percentage might be. With gods as a group, we don't know the probability that they exist even if we have no evidence. For individual gods it becomes more interesting, some of those have some claim as a base that if disproven, disproves that god also. For the displeasure of antitheists, they sometimes spend a lot of time trying to disprove gods that have a smaller group of believers than they seem to assume.

Things get more interesting with gods that have evidence, but it's not scientific but personal. It's your personal philosopher's stone, one that others think worthless but is worthy for you.

 

[Brickjectivity]

You can test for God's existence only if you have a definition of what God is, and does this fact equal an argument against God's existence? In some ways yes, because human minds create definitions. If God cannot be defined and tested for then in what way is God relevant to human minds, and if God is not relevant then how can God exist? Aren't things that exist relevant? You cannot test for an undefined God, but you might test for the existence of a relevant one. You might use your personal life history to make a determination about it.

 

[Unveiled Artist]

nor conclusive evidence for the existence of a god. The essential question then is whether or not the lack of sufficient and/or conclusive evidence for the existence of a god provides us with sufficient and/or conclusive evidence that a god does not exist?

No. But evidence that proves the contrary can prove he doesn't.

Or more simply, if there is no evidence for a god, does that mean there is no god?

No. But usually we know something does not exist when have evidence to assume the opposite is true. Since its religious in nature, there is much less objectivity in the evidence that disproves am existence of a deity/being.

On the surface, we might quickly answer "no". That is, we might say that the lack of evidence does not mean there is no god. After all, is not Martin Rees' aphorism correct: "Absence of evidence is not evidence of absence"?

....

But what about cases in which a lack of evidence for something does indeed suggest that something does not exist or is not present? For instance: Suppose your doctor tests you for cancer. No cancer is found. Isn't that evidence that there actually is no cancer?

No. They do process of elimination. When they are finished, and there is no cancer detected, we conclude the absence of it. We also find out because of lack of symptoms associated with cancer. If there is a similar illness that is more appropriate diagnosis, they go by that rather than disproving a negative. Since doctors aren't philosophers, they go with what they know and observe.

Can we assume that, if a god existed, evidence for that god could be discovered by "qualified investigators"?

Depending on how you define god. As a deity, it depends on the nature of its existence. What is god to where investigators will know without applying their bias in what they are searching for.

If we answer "yes" to that question, then why yes? And if we answer "no" to that question, then why no?

above

 

[HonestJoe]

What does any of that have to do with the OP?

You core question would very much depend on the exact nature of the god (or gods) that existed so that aspect seems entirely relevant. The part about the relevance and practical consequence of any answer we reach was building up from the foundations of your post.

 

[YmirGF]

PLEASE NOTE WELL: This thread is about the logic of arguing that a god does not exist based on the absence of any evidence for that god's existence. This thread is NOT about whether there is or is not evidence for the existence of a god. All posts that attempt to assert evidence for the existence of god will be considered off topic and ruthlessly deleted faster than a seventeen year old virgin can shed his or her pants on prom night.​

For the purposes of this thread, please begin by assuming that there is neither sufficient nor conclusive evidence for the existence of a god. The essential question then is whether or not the lack of sufficient and/or conclusive evidence for the existence of a god provides us with sufficient and/or conclusive evidence that a god does not exist?

Or more simply, if there is no evidence for a god, does that mean there is no god?

On the surface, we might quickly answer "no". That is, we might say that the lack of evidence does not mean there is no god. After all, is not Martin Rees' aphorism correct: "Absence of evidence is not evidence of absence"?

But what about cases in which a lack of evidence for something does indeed suggest that something does not exist or is not present? For instance: Suppose your doctor tests you for cancer. No cancer is found. Isn't that evidence that there actually is no cancer?

Or, as the logician Irving Copi once wrote, "In some circumstances it can be safely assumed that if a certain event had occurred, evidence of it could be discovered by qualified investigators. In such circumstances it is perfectly reasonable to take the absence of proof of its occurrence as positive proof of its non-occurrence."

Can we assume that, if a god existed, evidence for that god could be discovered by "qualified investigators"?

If we answer "yes" to that question, then why yes? And if we answer "no" to that question, then why no?

Wouldn't it depend on the size of the data set? Using your example of cancer, the human body is a limited data set. I do not to test another body to look for cancer in you. All I need is test you. The god question is much, much broader and we do not know the possible extents that would have to be investigated in order to arrive at an educated guess. It's sort of like sending a probe to chart the edge of the universe. The probe would never get to the edge of the universe due to the ongoing expansion. (I hope that makes sense.)

It also depends how formal one is being in this determination. If the bar of evidence is decided by a 6 year old, a lot of things might be accepted that would otherwise be rejected. If the bar of evidence is decided by a scientific panel of PHd's then the bar of acceptance would be considerably higher.

Likewise, with a question about god, can you really afford to write off mountains and mountains of anecdotal evidence. That has to count for something!

In regards to your final question, the answer is unknown. There is simply no way to determine the answer because we do not know how large a data set is required TO make a determination.

 

[9-10ths_Penguin]

PLEASE NOTE WELL: This thread is about the logic of arguing that a god does not exist based on the absence of any evidence for that god's existence. This thread is NOT about whether there is or is not evidence for the existence of a god. All posts that attempt to assert evidence for the existence of god will be considered off topic and ruthlessly deleted faster than a seventeen year old virgin can shed his or her pants on prom night.​

For the purposes of this thread, please begin by assuming that there is neither sufficient nor conclusive evidence for the existence of a god. The essential question then is whether or not the lack of sufficient and/or conclusive evidence for the existence of a god provides us with sufficient and/or conclusive evidence that a god does not exist?

Or more simply, if there is no evidence for a god, does that mean there is no god?

On the surface, we might quickly answer "no". That is, we might say that the lack of evidence does not mean there is no god. After all, is not Martin Rees' aphorism correct: "Absence of evidence is not evidence of absence"?

No, it's not correct. As you and others pointed out, an absence of evidence is at least evidence of absence while not being proof of absence.

And it can be elevated to proof of absence in a couple of special cases:

1. Where the necessary investigation is naturally limited. For instance, if I thoroughly examine a dog carrier and find no dogs, I can conclude that there are no dogs in it. The search domain is small enough that I can investigate it thoroughly, and the fact that "dog" has an established meaning means I don't have to worry about invisible, incorporeal, or microscopic dogs that would have escaped my notice.

2. Where the evidence is a necessary implication of the existence of the thing. You can think of this like a corollary of the old expression "where there's smoke, there's fire;" the flipside of this is that where there's no smoke, there's no fire: if I look around a room and find no hint of smoke, then I can conclude that there isn't a raging fire in the room, because if there was, the room would be filled with smoke.

But what about cases in which a lack of evidence for something does indeed suggest that something does not exist or is not present? For instance: Suppose your doctor tests you for cancer. No cancer is found. Isn't that evidence that there actually is no cancer?

Or, as the logician Irving Copi once wrote, "In some circumstances it can be safely assumed that if a certain event had occurred, evidence of it could be discovered by qualified investigators. In such circumstances it is perfectly reasonable to take the absence of proof of its occurrence as positive proof of its non-occurrence."

Can we assume that, if a god existed, evidence for that god could be discovered by "qualified investigators"?

If we answer "yes" to that question, then why yes? And if we answer "no" to that question, then why no?

It depends on the god. Some are unfalsifiable. IMO, likely fabricated to be unfalsifiable, but unfalsifiable nonetheless and therefore can't be disproven.

But really, it's pretty rare for me to care about whether a god can be disproven. It's irrelevant to me virtually all of the time.

When we're talking about that fine line between full-blown disproof and mere lack of evidence, we're really talking about the line between a god that definitely doesn't exist and a god that is indistinguishable in every way we know from a god that doesn't exist.

This irrelevant god isn't the god that any theist believes in. It isn't even a god that is capable of instilling belief in a person. By taking it as given that there is no evidence for gods, we're really saying that every theist ever has been unjustified and unreasonable in assuming that their god(s) exist, even though we can't absolutely exclude the possibility that they serendipitously stumbled on the right conclusion in an "a stopped clock is right twice a day" kind of way.

We're still taking as given that anything in any religion that would serve as evidence for gods if it was true is necessarily unfounded: no prophets are genuine, no "revealed" scriptures actually came from God, no divine miracles ever actually happened... or at least if they did, there's no valid way to attribute them to any gods.


... so by the time the question of lack of evidence vs. proof of non-existence matters, we've already concluded that every theist anywhere is unjustified in their beliefs and that virtually every theistic religion is at best built on nothing and at worst is completely wrong.

 

[exchemist]

What makes you certain that evidence for the existence of a god -- if there was such evidence -- would be readily available to the man on the Clapham ominbus, and not require any special qualifications to discern it? Just curious what your reasoning is.

I have not expressed any opinion about that issue. My sole point has been that absence of evidence can, in general, be evidence of absence.

To address the question of evidence for God's existence, I suggest you may want to distinguish, next, between forms of evidence.

Objective evidence - or as close to that as we can get, viz. scientific, reproducible evidence - seems to be lacking. Indeed it is hard to see what form this could take, short of a well-attested and documented gross overturning of the principles of nature, directed towards some apparent goal.

But if subjective evidence, appealing to individuals via the psyche and feelings but not objectively communicable, is admitted, it seems to be rather a less clear story.

As to what form of special expertise, if any, could investigate this, the best answer might be psychology.

 

[9-10ths_Penguin]

What if we have good reason to believe there are no "qualified investigators" when it comes to fairies? Can we still say absence of evidence for fairies can be evidence of absence?

Please note: I am neither asserting there are or there are not qualified investigators. I am merely asking as a hypothetical, what if we had good reason to believe there were none?

If, for whatever reason, we need special qualifications to deduce whether there are fairies or gods in the garden, then when someone with similar qualifications to me claims that there are fairies - or gods - in the garden, I can dismiss their claim as unjustified.