Those brainy physics guys define "reality" in a few different ways so they know what kind of reality they mean, because it's important in physics to distinguish. Probably for us too, when we start talking about science, religion, metaphysics, etc.
1. Phenomenological reality: That's the kind PS up there is talking about, the relative nature of reality as experienced by the individual. Each person's subjective reality is particular to them and probably in every aspect experienced ONLY by them..unless you're a telepath or an empath of some sort and can share your exact reality with someone that way...highly debatable, if not a fun and interesting Scifi concept.
2. Truth: that word that ex Witnesses are so allergic to. LOL But, in scientific terms, not used the way many use it, which is better defined as number one definition of reality, subjective or phenomenological reality. Truth is a toughy, because various definitions are valid. Metaphysical truth is not scientific truth but they are both truth. Okay?
Scientific truth is what you can prove to exist through scientific method. That's it.
The rest is nebulous stuff that is better left to long winded dudes like Proust and Kant...or Nietchze...those guys who apparently have a lot of time for navel gazing on their hands. There's all kinds of stuff like "consensus reality" . If enough of us say it's real, then by damn, it's real! Like believing that green paper can buy food and a place to live, for example, that's the consensus reality of American paper money.
It's also what allows different religions to exist, because enough people got together and said, "Yep, this is what God is, this is what he says, this is what he wants, and we're going with that, and I don't care what you say it is, this is what WE say it is." Consensus reality is also the basis for a good many other social concepts, like political parties. As you can probably tell, Consensus reality leads to a lot of debates and hassles over what is so and what isn't so, but we seem to need it.
If you're a strictly a realist, (kind of boring in my humble opinion, but some people like the same sandwich every time they go to Subway, too) you want truth to be "just the facts, Ma'am" and Joe Friday is your god...well, at least your role model. Realists like their truth served up with lots of concrete proof, and just to be able to grab hold of the truth by it's big truthy butt and hold it tight against the unreality of life, which can get pretty damn unreal at times. A lot of engineers I know thank God, are realists. When I'm in a plane, by golly, I want it designed by a guy who backs up every bit of his design with mathematical proof that the plane is going to stay in the air.
If you're an anti-realist, your goal is to touch every realist and blow them up...LOL...no, it means simply that you have a more flexible notion of the truth... the inaccessibility of any final, objective truth means that there is no truth beyond the socially-accepted consensus. (Although this means there are many truths, not a single truth.) I'm like that, which is why I'm a Universalist Unitarian. A realist is going to think I'm flakier than hell, but um...remember, in terms of physics, ALL of these theories of the truth are VALID. So, don't be dissing a sistah simply because she has some weird notions of truth, kay?
3. Fact: A fact or factual entity is a phenomenon that is perceived as an elemental principle. It is rarely one that could be subject to personal interpretation. Instead, it is most often an observed phenomenon of the natural world. The proposition that "viewed from most places on Earth, the Sun rises in the east" is a fact. It is a fact for people belonging to any group or nationality, regardless of which language they speak or which part of the hemisphere they come from.
Basically, Copernicus and Gallileo were right, The Catholic Church was wrong (they weren't even going by the Bible, but by Ptolemy, a Greek dude, because the Catholics have always entirely fond of Greek Philosophy, another topic entirely, so IN your FACE WTS, the Catholics weren't misreading the Bible at all about that) and we still believe the sun is the center of the solar system because it's OBSERVABLE, no matter how much the Church paddles your behind because it wants to be right.
This is the reality that Phillip K. Dick, the science fiction writer defined when he said, "Reality is that which, when you stop believing in it, doesn't go away".
