you pocket some loose change before leaving your home—glancing at the coins briefly before pocketing them, and you tell yourself, "there's three quarters in there." then you get to the point of buying something with the change, and now it seems there's only two quarters. what's happened?
well...any of a number of things could have happened, but whatever the explanation, you have had a miniature liminal experience—a perception on the boundary of uncertainty. maybe you really saw three quarters, or maybe you didn't. I think most of us would accept that we'd miscounted. maybe we mistook a nickel for a quarter. maybe some wishful thinking warped our perception just a little, making us want to see three quarters. and I think most of us would shrug and accept the minor inconvenience.
but maybe you felt so certain about the three quarters! and that's where trouble can start, because if you decide that there really had been three quarters but found only two in your pocket later, then obviously the third quarter must have gone somewhere, and maybe you're not inclined to write off 25¢ as a trivial loss. and it isn't, really—a quarter can mean the difference between eating and not eating, if you have no money. so you go rummaging through all your pockets, checking the ground, checking everywhere you've walked, go back and tear up your place, looking for the quarter and perhaps never finding it.
if you're worried enough...you might decide that somehow you'd been robbed, and even think of accusing someone.
what I've just described might seem silly, unimportant. but there's a great difference among people in the degree of uncertainty that they accept in their lives and from their routine perceptions. we (of the Pnictogen Wing), with all our humiliating years of experience in dealing with how our mental and neurological issues scramble our perceptions and memory, have come to be pretty tolerant of mistakes and incongruities in our own awareness of things. take our amblyopia, for example, which means that we've often been shockingly bad at judging positions and distances of things—we'd be fools to put too much trust in a hasty glance. we are used to having all of our perceptions accompanied by an undertow of self-doubt.
there do exist folks, though, who place absolute faith in the correctness of their hasty glances, all of them, all the time, no matter the circumstances. I suppose for them the alternative—i.e. the undertow of self-doubt—is simply too frightening to contemplate: if they were brought to the point of doubting even one of their perceptions, then they'd have no reason not to doubt all of them, and they refuse to live with constant doubt.
that's too bad. really it is. because I feel like everyone should be used to doubting themselves. I believe it's necessary, in fact.
~Chara of Pnictogen