If we're working under the definition that it's something which is true regardless of how a person feels about it, then I think it can be found through non-verb

If we're working under the definition that it's something which is true regardless of how a person feels about it, then I think it can be found through non-verbal means. For example, if I claim to my insurance company that my house burned down yesterday, they are going to want objective measurements to ensure that's true. The problem comes down to what happens the further away from an event you get. I can claim my house burned down twenty years ago and it would be more difficult to prove me wrong. But you could still use things like police reports, satellite photographs, interviewing people alive at that time, etc. to provide what I would consider objective truth. Of course, you can always play the pessimist view and assume everyone and everything is a lie. Which is valid, I suppose, but not very useful.