Plato always argued with this one, he pondered what makes a bed? al beds are diferent yet we can all identify a bed yet all beds are different. plato finally decided that there ahd to be a spiritual force that told us what a bed was. then aristotle came along and said that there was an essence in every thing that was invisible to the eye yet still there (like if you put honey in milk, the mixture will still be white but it still has honey in it). so here is my question what is a bed? how can we identify a bed so easily?