Okay, let's start over. Let's go with your phrase, or rather the phrase you've been parroting (because I'm sure you're using it because you've heard it somewhere), "all smoke but no fire". This question intuitively, almost automatically, leads to the question "well, if not fire, then what the hell is producing all that smoke?"
The entire point of the fire and smoke metaphor is to describe the validity of indirect evidence. As you have more and more indirect evidence of something, even if that something hasn't been directly observed, it because more and more exceedingly unlikely that that something isn't true. This is, by the way, pretty much the way all science works now-a-days.
The fact that you don't realize this tells me that you're just parroting a phrase that you've heard somewhere and haven't thought critically about the words you are speaking.