> Einstein for example rejected a very simple idea of time, and reinvented it to create the theory of relativity. But that _really_ isn't what he did! He start

> Einstein for example rejected a very simple idea of time, and reinvented it to create the theory of relativity. But that _really_ isn't what he did! He started from the seemingly obvious notion of linear time. Added the _observation_ of the finite speed of light. And _noticed_ that the "obvious" notion of linear time leads to contradictions (basically saying "at the same time" has different meanings for different observers). And from that he _had_ to go out and construct relativity in order to reconcile these contradictions. Does it matter to anyone? In practice? Probably not. As long as you do not get close to the speed of light (either in velocity or in mass. Yes.. that statement makes sense as is) relativity really is indistinguishable from our notion of linear time. This is _necessary_ for relativity to be a useful theory. But it is _also_ a massive shift in how we think about the world. That's the danger with "intuitive" understandings. They can only ever be based on experiences and those do not lend themselves to extrapolations. The 2nd law of thermodynamics is one of those things. It seems completely obvious if learn about it the first time. Then you go a bit deeper, start picking it a part, thinking about the second and third order consequences of it. Then you argue a bit about whether the probabilistic formulations are worth anything in the first place, then you try to reconcile it with information theory. At this point you get into the whole quantum mess and ask yourself how this "law" can hold in all these circumstance, even if it doesn't seem to have any reason to mean anything anymore.