As much as I agree with everything you have just said, I also disagree.

Not really. You're spot on.

Okay, almost. Things kind fall apart starting with the second-to-last sentence. If I have quantifiable evidence of something's existence, then I won't "believe" it, I will know it or treat it as a given, whatever applies in the current context. By definition, "belief" is reserved for things that are taken on faith; "rigorous proof" need not apply. I don't believe that I am a human, I know I am. I don't believe that I love pizza, I know I do. On the other hand, I believe that my children love me, but unless I can tap their internal dialogue, get a read on their thoughts and feelings, I'll never truly know whether or not they do. (They do. . . . Right?)

We take many things on faith and call that faith "knowledge," perhaps without realizing it. For example, I know that the world is round. But do I? Have I seen the world while in orbit? No. Have I taken the measures and then done the calculations necessary to prove definitively (to me, at any rate, more on that later) that the world is more grapelike than pizzalike? (And for someone who loves pizza as much as I do, the flat-earth theory is beguiling.) Again, no. In literal terms, then, my knowledge that the world is round is, in fact, a form of belief. Someone took pictures, you say. Sure, but maybe those pictures were faked. Someone measured and calculated, you insist. Sure, but maybe the measures and/or calculations were flawed; maybe the person who did the work lied. I don't believe that, by the way, but there it is: belief.

We draw lines--pretty much constantly. I will believe this and call it reality because it falls in with my vision of what reality is. That idea that occupies the space on the other side of my internal line-- That's crap. Proof that the world is round is definitive to me; to the real flat-earthers, it is so much propaganda, worth naught but a snort of scorn. In the end, it is all personal perspective. We decide, consciously or un-, what is real and what is not. I know people who are 100%, can't be wrong (scream obscenities at the person who implies they are) certain that there is an entity that they call "god"--well, "God." Are you really prepared to say that they are doing no more than state an opinion?

This is where English fall flat on its face. Yes, those people whom I've mentioned are of the opinion that god exists. Yet, in their personal worldviews, they are speaking facts, not opinions. Are they wrong? Are you (for insisting that it is an opinion and not a statement of fact)? We have no easy way (that I have found) to incorporate this is true and accurate as far as I am concerned, but, depending on your interpretation of the evidence, might be for you a matter of faith and/or opinion into our proclamations of truth and reality. And even if we did, would the person who "knows" something to be as he or she knows it to be actually include it? Doing so would undermine that claim of knowledge, so . . . Picture that rabid religious nut who lives down the hall. Is he going to add that shade of meaning to his statement that "God exists"? Perhaps belief becomes knowledge if it is strong enough. No? Well, I agree with you there, but that is only my opinion.