... therefore God does not exist.
This statement fails on two points of logic.
The first is that of an Argument from Ignorance.
This is when we illegitimately appeal to ignorance to support a conclusion. It usually takes the following form:
“No one has proven not A, therefore A is true,” or
“No one has proven A, so A is false.”
The fallacy is mistakenly believing something must be false because it has not been proven true, or that something must be true because it has not been proven false.
A secondary flaw is the fallacy of misplacing the burden of proof
Arises when someone is misled into thinking they have to prove a claim (eg that God exists), when their opponent should be proving his claim (that God does not).
The point here is who is making the claim? The claimant, be they theist or atheist, in making a claim, shoulders the burden of proof for their claim.
For example, the person making a positive assertion usually has the burden of proof (e.g. the theist who asserts God’s existence). Once the theist presents an argument for God’s existence, the burden of proof is now on the atheist who denies God’s existence. Once the atheist shows what is wrong with the argument or presents a new argument against God’s existence, some or all of the burden shifts back to the theist. And so it continues.
(From the Lucid Philosophy website)
Further discussion of the Burden of Proof here
This statement fails on two points of logic.
The first is that of an Argument from Ignorance.
This is when we illegitimately appeal to ignorance to support a conclusion. It usually takes the following form:
“No one has proven not A, therefore A is true,” or
“No one has proven A, so A is false.”
The fallacy is mistakenly believing something must be false because it has not been proven true, or that something must be true because it has not been proven false.
A secondary flaw is the fallacy of misplacing the burden of proof
Arises when someone is misled into thinking they have to prove a claim (eg that God exists), when their opponent should be proving his claim (that God does not).
The point here is who is making the claim? The claimant, be they theist or atheist, in making a claim, shoulders the burden of proof for their claim.
For example, the person making a positive assertion usually has the burden of proof (e.g. the theist who asserts God’s existence). Once the theist presents an argument for God’s existence, the burden of proof is now on the atheist who denies God’s existence. Once the atheist shows what is wrong with the argument or presents a new argument against God’s existence, some or all of the burden shifts back to the theist. And so it continues.
(From the Lucid Philosophy website)
Further discussion of the Burden of Proof here