Argument based on speculation

I was wondering if it is acceptable to argue a point that cannot be proven. For example; Person A states that majority of people on this earth have never stolen anything in their life. Would it be acceptable to argue against Person A using speculation as to why the majority of people have stolen at least once(human nature, etc)?

>>3
No, that would be a bullshit argument. You can't do anything more with the information you have than argue that stealing seems pretty universally easy and attractive to you.

Not that you couldn't convince some people with clever writing and a good imagination, but that doesn't mean you have a good argument. Just a bad audience.