There may be fairies at the bottom of the garden. There is no evidence for it, but you can't prove that there aren't any, so shouldn't we be agnostic with respect to fairies?
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A guided missile corrects its trajectory as it flies, homing in, say, on the heat of a jet plane's exhaust. A great improvement on a simple ballistic shell, it still cannot discriminate particular targets. It could not zero in on a designated New York skyscraper if launched from as far away as Boston.
An Internet meme is a hijacking of the original idea. Instead of mutating by random change and spreading by a form of Darwinian selection, Internet memes are altered deliberately by human creativity. There is no attempt at accuracy of copying, as with genes - and as with memes in their original version.