David Blomstrom

"You can't prove a negative"

It's reported that a politician who's a notable right-winger threatened to nuke another country years ago. However, there isn't enough evidence to substantiate the claim.

One of his supporters says, "You can't prove he said that."

I counter, "You can't prove he did NOT say that. Moreover, he has threatened to nuke other countries. Therefore, this rumor can't be proved or disproved, but I consider it believable."

The supporter then says "You can't prove a negative."

Is this a fallacy or just some kind of obfuscation or diversion? I'm not even sure what a "negative" is.
asked on Saturday, Sep 14, 2019 05:06:44 PM by David Blomstrom

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It is often possible to prove a negative, although sometimes it's difficult.

But we have the concept of burden of proof. If you say that the guy threatened to nuke someone, it is your job to prove it. This time, I think the fallacy is on you.
answered on Saturday, Sep 14, 2019 05:12:50 PM by Bill


Within the English language, it is grammatically correct to use a "double negative", It's called the rule of double negation.

Consider this, is "you cannot do something" provable?
E.g. You cannot jump off the international space station at its current location and land on Pluto.
If "you cannot prove a negative" is true, then you've just proven "you cannot do something"....You cannot prove a negative is itself a negative. The statement is a self-contradiction.
Link to an explanation....
answered on Sunday, Sep 15, 2019 04:21:51 AM by skips777