The thing we really have to come to terms with is that the future is unpredictable. Both the "doomers" and the pollyannas fall down here. Past performance says

The thing we really have to come to terms with is that the future is unpredictable. Both the "doomers" and the pollyannas fall down here. Past performance says nothing whatsoever about future performance. Nice well-behaved Newtonian systems are amenable to prediction by mathematical regression. Messy, complex, chaotic living systems are not. Everything changes, and changes how it changes, and changes how it changes how it changes, and ...