Well, using pure reason, you can assume one of two things:
Either A, There's no such thing as secret societies, and for whatever reason (perhaps I'm a crazy person, or I've been lied to, or I just like to make shit up to see what the idiots out there will believe, and I'm not alone, because there are people who have devoted their careers to studying secret societies), there have been these crazy myths about people getting together and being secret about secret stuff instead of just drinking beer and watching football like everyone else. People don't keep secrets from one-another, they don't share hidden allegiences, and people whose beliefs are counter to what mainstream society believes won't hide their beliefs to avoid persecution.
Or B, Secret societies DO exist, and you simply haven't had personal contact with them or anyone that has (that you know of). If I had made the assertion that Golden-Lion Tamarins exist, you probably would've believed me, even though you've never seen one - they're rare - but they do exist.
As for my friends, I don't think they'd appreciate me mentioning them or the societies they belong to. I can name the more "public" of societies, like the Freemasons, Khlysty, and the Esoteric Order of the Golden Dawn, but know that there are a great deal of "subsects" and secret orders WITHIN these societies. In many cases, the society itself is not "secret" per se, like the Masons, but they HAVE secrets, and there ARE secret orders and subsects within the overall society.
So, either I'm crazy or I'm lying to you (and have zero motivation to do either one of these things), or I'm telling the truth, and you've made incorrect assumptions about the world. Have I lied to you before? Have you made incorrect assumptions about things before?
Think about it logically for a minute.