The skeleton is most often used to signify death, but there are other interpretations. A skeleton is also a symbol for an underlying, truth, or the overall human condition as said "beneath all of the different skin colors, ethnic variations, etc., the bones remain the same".. Combine the 'truth' meaning with the fact that bones last longer than the rest of the body and you get 'enduring truth.
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The skull, seperated from the skeletonm with a candle stuck in it, has become a symbol for black magic and the skull combined with books is seen as a symbol for science and/or history. The traditional symbolization of death is a skeleton, carrying a sickle or scythe, hence The Grim Reaper
