So, I was going through and flagging new answers to old questions (because that's fun) and it dawned on me, are opinions really answers? The obvious answer is "yes" and that wrong opinions should be downvoted. But let me present an example and then I'll open the floor for discussion and laying of guidelines.
Here's an example question that I just thought up (no doubt it's been asked before but that isn't the point of this):
Q: How can two massless photons interact to form a massive particle-antiparticle pair? And where does all that extra energy for the new masses come from?
Now, there's three distinct types of answers you can get for this. First, there's the answer based on physics, expertise, and referencing:
A1: Pair production occurs through multiple processes. The zero-loop Feynman diagrams (shown below) for this process show the most common of them. The energy for the final pair comes from......... (You get the idea)
The second type of answer combines knowledge and opinion. It is usually from someone that doesn't know the exact physics, but knows enough to make it up as they go along (although it may not be right):
A2: I'm not a particle physicist but I think it probably has to do with quantum mechanics and the energy of photons. Quantum mechanics says anything that can happen does happen and this is something that can happen with a non-zero probability. The energy for the final pair probably comes from the energy of the photons transferred to mass by E=mc^2. And then the momentum of the new particles must be whatever's left over.
The third type of answer is purely opinion and rarely has anything to do with physics:
A3: I thought about this myself and it's my personal belief, which seems fairly obvious once you think about it, is that God had to make all the particles at some point, so he allowed this to be possible so he could get the energy from somewhere. That's the simplest answer, the physicists just have made it all confused to hide that they can't quite grasp how it really works.
Okay, here's my analysis. A1 isn't in question; no opinion, all answer. A2 uses opinion but it also uses physics and intuition to form, what I'd call, a valid if not completely correct answer. A3 is pure opinion. Obviously the thing to do is downvote it and maybe leave a comment to the effect of "this isn't a place for personal opinions". But is it truly an answer?
I'd love to hear what everyone thinks on whether things like A3 are really answers (N.B. By "like A3" I'm not referring specifically to religious stuff. Anything that's so obviously pure opinion and no physics). To start off the discussion, I'll provide two points of view, one for and one against. Perhaps we can discuss and, if necessary, amend guidelines.
Yes, they're answers
Perhaps the easiest to argue, A3 attempts to answer the question. It asks how the process can happen and it gives an answer. The answer is admittedly unscientific, wrong, and generally poor, but it presents an idea that, if true, would sate the asker's curiosity.
To call it not an answer would mean we could flag it and remove it as such. This opens us up to a wide range of potential abuse. Where do we draw the line between purely opinion and an acceptable mix of opinion and physics? This should be downvoted, but not deleted.
No, they're not answers
An answer to the question must do just that; answer the question. The question is asking "How does this happen?", not "What is your opinion of how this happens?". If I asked "Why is the sky blue?" and you responded with "In my opinion, it's blue because it reflects the ocean." I'd say "I didn't ask you what your opinion was, nor do I care what it is. I want to know the accepted explanation, your opinion is irrelevant." (And then I might literally bite your head off too).
This is the essence of what I'm saying. If it asks for the physics explanation, does it really count as an answer if someone gives their opinion? Shouldn't A3 be flagged as not an answer? After all, the appropriate comment to be made is "The OP asked for the explanation of this process not your opinion of what it might actually be." If the question were "What is your opinion of X?", it would be closed as primarily opinion-based. Doesn't that suggest the question "How does X work?" is sufficiently different and that a valid answer to the former would be sufficiently different from a valid answer to the latter?
Okay, there's two points of view. I think both have their strengths. I'm leaning on the side of "Yes", but I wouldn't be making this post if I didn't have strong enough doubts to seriously consider "No". So let's have a fun discussion (no heated debates, please). What do you think? And if you also think A2 shouldn't be considered an answer, I especially want to hear from you.