First of all, i Hope u ll understand me: english isn't my first language and talking about philosophy Is not that Easy for me. I see a pretty big fallacy in ur argument: if, Indeed the world has no meaning, u cant talk bout some "survival mechanism": ur trying to give meaning to something that ur saying doesnt have meaning (even the mere purpose of survival Is a meaning: the world exist in order to continue existing). When u say something dont have any meaning u cabt Say anything else, because u Will inevitably end up organizing that thing (Kant explain this really really well, prolly u know that better than me, judging on the terminology u used) and, doing so, giving a meaning to that thing only becouse in some way It appears ti u as a phenomena. As I said earlier: that thing exist in order to continue existing. That Is a meaning. Because of this to do such argument as yours u have to suppose not that the world doesnt have a meaning, but that It has and u cant possibly know It. I really Hope u explained myself at least a bit, but i lack of all english philosphical terminology, so i dont think so: if u think what i wrote doesnt male any sense probably ur right.