These are four different things. Though it is confusing if you don't think about it and the difference may seem largely irrelevant.
I have already acquiesced on the differences between these things, that is not what I was calling arbitrary, in your example, while you may feel you have sufficient evidence to claim God does not exist and do not have enough evidence to claim that we were or weren't created to me seems arbitrary or defined by what are to me unknown stipulations. We obviously cannot disprove God, we can only provide evidence which may lean us towards a particular stance and the same thing can be done for many things which cannot be known with certainty to be true or false. You reject the Christian God on what you consider to be evidence, yet clearly much of the world feels that you are wrong but you would critique anyone with a stronger stance than uncertainty with regards to other questions without clear answers such as whether we are created or not, whether there is meaning/purpose or not.
I think in your 1st category, one who doesn't know with certainty that (whatever) is not real - yet don't entertain the possibility at all, even thinks badly of those who do believe and would argue against believing based on a particular principle about the requirements for belief and those who fail to meet it. An agnostic also may recognise although they believe the issue to be unsolvable or unapproachable yet have a hostile opinion towards those who believe or perhaps even a hostile opinion to the 2nd and 3rd categories because they believe one who takes a strong stance on an issue of faith/principle to be deluded or oblivious. I reject your simple classifications for how each category defines the nature of any particular stance and this is why I am still unsure of what to think about what this means for my definitions of nihilism and atheism quite yet.
So if you say there is no purpose. That is a positive claim for which you need evidence. I am position 4 on if there is a purpose.
I view the evidence to be overwhelmingly in my favour, I just admit that I lack proof. I may go into detail about all the things that make nihilism the more reasonable position (as far as a position 1 goes on your list) and perhaps even a position 3 for some including myself. I think the evidence for nihilism is far greater than what exists for atheism and as a result of this evidence my position for nihilism is the 3rd. However just to go back into what I was saying previously, the differences between all four of the aforementioned positions are essentially preferences and I say that mainly because you have said you take position 3 on things which we have no proof do not exist.
Position 1 is simply saying the argument is unconvincing, no evidence of this is required, you will be position 1 if you say you are
Position 2 You are basically stating a preference for other peoples behaviour and arguing for it, if you say this is your position then it is, no evidence is required here, it is just your personal belief
Position 3 You say you need evidence but not proof, what is decided as being evidence can be contested and debated due to nature of the subject, the amount of evidence required for the position is not stipulated and as a result of all these things, you are to judge whether you have enough evidence and whether your evidence is valid or not. In the end, you can pretty much decide that you have enough (information you classify as evidence) as you wish.
Position 4 can be said to be either a position of principle or an interpretation of the information they have access to, either way one will arrive at this position as they wish and without requiring an argument/evidence, it is simply their opinion.
So surely you would agree that assuming I cannot give proof against objective meaning/purpose, that how convincing my argument would be has little to do with anything except for how it impacts you, if you like it or not. This is why it would be great if I could capitalise on some principles that would allow me to make an argument of alignment (dunno if you get what this means yet or not but whatever) as it would be more compelling. A lot of whether I can or not depends on the definition of nihilism. Whether it is simply a lack of belief, or a conviction against the existence of objective meaning/purpose... would determine whether the aforementioned principles would lead someone to nihilism. Whether I am content if I cannot do this depends on what course of action an agnostic of objective meaning/purpose determines, will it be essentially nihilism without conviction? Or will they live their lives without giving it much thought? Or even under the pretense that they are real? My argument against such people would naturally use an argument of alignment and I guess I will have to consider my options if I wish to continue arguing for nihilism.
Would be being closer to or further away from reality aid survival in this long term million year long time span? What kinds of things would destroy us?
I just don't think you use the word reality sensibly, where in reality does it say "do not destroy your planet with bombs, it is not sensible to do that"??? If a guy wants to destroy the world for lols, or for a feeling of power or as a last **** you to those who insulted him, how can you turn around and say "that is not close to reality... you are so far away from reality!!.. Reality will correct!"? It truly boggles my mind how you use the word reality, I now assume whenever you say reality what you mean is "whatever I think to be reasonable" and when I do that, everything you say makes a lot more sense.
Again you are missing the point.
I said that I wanted to hear out your argument and then rebut it but there is no argument beyond "perhaps there is a pattern here, perhaps that pattern will result in something". Drunk people stabbing randoms, people driving cars too fast and dying or people getting rekt by gravity; the people who do such things may have been influenced by genetics and by doing what they do - slowly reduce the percentage of people with that gene. My response to this was that I recognise these patterns but they are not necessarily doing us any favours, you are thinking about it in a way which only considers extreme circumstances, mostly revolving around death. Now I am not an expert on genetics, homosexuality seems to be genetic yet still exists, many conditions like this which ought (based on the simplest understanding of evolution) to be bred out, are not being bred out of. The big reasons that people have a lot of children or no children however is not based on whether you are stabbed to death, or drive your car into a tree, it is based on far more subtle things. Your education, your place of birth, your ethnicity, your socioeconomic status, your IQ and so on, are clearly recognised factors in how likely you are to reproduce and how many children you are likely to have. When you involve factors like these, you no longer have this picture of degenerates and fools being taken out of genetic circulation, leading to a world where anything is "corrected" by anything. Instead you see a picture of causality, where more often than not, more intelligent, more educated, more privileged people are getting significantly out bred by underachievers, lower IQs and that those of a particular ethnicity are out breeding others due to culture and factors which are not genetic but lead to a difference in the overall genetic pool.
Government policies, economics, culture and so much more goes into who reproduces, how much and there are a lot of factors that are not genetic to do with who survives and who doesn't. Things like "saving people" are again, not distinguishable patterns that you've made any attempt to demonstrate, instead you feel that because the impact is unknown, maybe the impact is a pattern. Perhaps not all of what I have said is relevant to what you are saying because honestly most of what you are saying is complete gibberish to me, I am still waiting for that moment that you give an explanation that makes sense. You have in some Frankenstein-like fashion intertwined quality of life, "reality" and evolution into some horrible monster too hideous to look at... I fear I have nothing more to say about this than I have just now, it is a truly unique and peculiar idea and perhaps it will make sense to somebody else but not me.