If you feel that spiders are going to kill you, and you act in accordance with this, then it is a belief, regardless of how it was obtained or why (ie, instinctual, reasoned, concious, unconcious.) Because even if it is an instinctual fear, once you are aware of it and choose to still act in accordance, then it is now conciously accepted.Ok - but is it then appropriate to say that this is my belief? I hardly think so. It might mean that I have doubts about just how sure I can be about whether or not spiders are dangerous, for instance - or whether or not I can be sure I'm looking at a "spider" in the first place, not somme other monstrosity. Or it might be a completely instinctual response with absolutely no conscious awareness.
Something, yes - something. But that does not imply that I believe that spiders are deadly/dangerous/poisonous, does it? For you to present me as having this belief to a third-party would be misleading, would it not?
Even then, I can hardly be said to be of a position that spiders are deadly, now can I?
If you did believe that spiders will kill you, then I also think it a reasonable assumption to assume that you believe the spider is deadly in some manner (as something cannot kill unless it is deadly.) Basically, we go through life making probability assumptions-- nothing is every 100% certain. This is necessary in order to operate in a world in which we never have complete knowledge; if we didn't, we would be immobilized, incapable of ever making any action. So, while, true, it is possible you are extremely irrational and do not believe that spiders are deadly while believing that spiders will kill you, that is the less likely explanation.