My response (below) to the internet atheist cliche: "You can't prove a negative."

FIRSTLY...

The claim is false, it is possible to prove a negative.

For example, I can prove (as more likely true than its opposite) :

- That there is no German money in my wallet.
- That there is not a one inch sized picture of the Queens head on my tea cup next to me.
- That my house is not made of oranges.
- That the prime minister of England is not a six year old girl.
- That there is no dog currently sat in my car.
etc...

SECONDLY...

If by saying, "You can't prove a negative" one actually means to say, "One can not prove a negative with absolute certainty.” Then this could be said to be equally true of proving a positive. For on the one hand (the negative) although our beliefs can be argued as not being certain due to limited knowledge; on the other hand (the positive) it could be argued our beliefs can not be certain due to possible cognitive/sensory malfunction.

THIRDLY...

If there are two competing and opposite propositions and you claim one of them is more likely true than its opposite (and that others should believe this), then you are making a positive knowledge claim and you have a burden of proof.

You do not need to prove a negative with certainty, you just need to show it is more likely true than false.

There are three ways you can show a proposition over its opposite as being more likely true; please click on the link below for more information:
https://www.facebook.com/notes/atheist-answers/how-a-proposition-is-weig...

FOURTHLY...

If it is true that there are no (possible) rational reasons which could support the claim that, ‘negative proposition (-X) is more likely true than false’ (which is not true, anyway), then all that would rationally follow from this is that one should not believe that the negative proposition is true over its positive opposite, or believe it is more likely true than false over its opposite.

The atheist cliche (above) is tantamount to saying, "There are no rational reasons to support belief in this negative claim..." with the added position, "...and there can never be any rational reason to support a negative claim as more likely true over its opposite positive claim."

Rationally we should only believe a claim over its opposite when we have rational reason to do so (not just blindly assume it), if a negative claim really does lack any rational reason to believe it and could never have any rational reason to believe it in principle, then we should not believe the negative claim as true or more likely true over its equal and opposite positive claim; yet a lot of people who say you can not prove a negative [because there are no rational reasons for belief in it] at the same time believe the negative claim is more likely true than its opposite positive claim.

There is also no principle which shows if a claim is negative it is more likely to be true than its equal and opposite claim (both are ultimately just claims about a set of affairs in reality). Let me give you some examples to demonstrate this:

(X: Positive Claim) The jumper I am wearing has a right sleeve.
(-X: Negative Claim) The jumper I am wearing has no right sleeve.

(X: Positive Claim) There are more stars which exist beyond those stars we have currently discovered.
(-X: Negative Claim) There are no more stars which exist beyond those stars we have currently discovered.

(X: Positive Claim) There is currently fuel in the petrol tank of my car.
(-X: Negative Claim) There is currently no fuel in the petrol tank of my car.

(X: Positive Claim) There is gold somewhere else in the universe other than earth.
(-X: Negative Claim) There is no gold somewhere else in the universe other than earth.

ETC...

As you can see there is no principle which makes a negative claim more likely true than its opposite positive claim. Rather each claim above is independent from other negative/positive claims and is weighed (for showing one as rationally justified over the other) on the three methods which I have given above (attached in the link).

FIFTHLY...

In the end of the day, this internet atheist cliche is claiming...

(A) In principle there are no possible REASONS one could have for believing a negative proposition as true or more likely true than its negation/opposite, and/or...
(B) If one could find REASONS for believing a negative proposition as true or more likely true, in principle it is not possible that any of these REASONS would/could be RATIONAL REASONS.

...which is clearly false. We can clearly see that there are rational reasons one could possibly have for believing a negative propositions as true or more likely true than false.

In the end of the day evidence is just a set of affairs (A) found in reality which rationally infer to supporting conclusion (X) or (-X).

One should not confuse there being no reason/evidence to support a claim with there being in principle no possible reason/evidence to support a claim. There may be no reason/evidence to support a certain negative claim because it is false, not because it is not possible in principle; especially if someone finds reason/evidence to support its opposite positive claim (if it is possible to support a positive claim (X) with reason/evidence then it is possible therefore in principle to support claim (-X) with reason/evidence; again, don’t confuse no available reason/evidence VS in principle there being no possible reason/evidence).

God bless