Timing and Perception is Everything

[Splendour]

Philosophy is such a confusing field. When I look at various philosophers one says this is the way things might be/are based on this perception then along comes another one and he says "No, No, No. This happens before that so this is the way that it is". I just lately discovered that Heidegger is saying that Western civilization and Plato got it all wrong and now there's Hume with his theory of causality: that our beliefs about cause and effect depend on sentiment, custom and habit, and not upon reason, nor upon abstract, timeless, general Laws of Nature. (theory of causality definition from wiki). So what came first? The chicken or the egg? Seems like philosophy points to the egg first then another philosopher points at the chicken then another philosopher comes along and we're all back to the egg. I'm starting to think they all get only a part of it right. They have this totalitarian approach that each one has to get everything right but the more we learn the more we find out there's more variables than we can keep track of and that psychology/sociology seems to impact everything and philosophers in particular.

Anyways, can anyone explain the main thrust of Heidegger's argument to me?