There are plenty of smart people who don't abuse substances. Plenty of those people are actively pushing to move the world ahead, and they're succeeding. Things are better now than ever. The people who see the bad in the world are going to be brighter and less oblivious, but that doesn't preclude the possibility of good and better things happening.
You can't possible believe this, can you? The notion that history is a steady, near-constant ascent for humanity is flawed.
Its a perfectly reasonable thing to believe--just like its opposite--and depends solely on how you're measuring. All in all, I think it depends on the reduce function. If it was reduce(lambda a,b: a+b,[ x.happiness for x in humanity ]), then maybe there is the most happy the world has ever seen. If you took that number and divided it by the population, than maybe the average happy per person has gotten lower. And so on and so on.
I think its definitely possible to believe it.
Well, when you put it that way, Batman...
I'm very optimistic for my own life and for things that I can manage. I'm not optimistic for humanity as a whole at any given time, nor am I pessimistic. History is history, and we are all victims of human nature. Good will happen, bad will happen, the lot of some will improve as the lot of others worsens.
I know humanity is capable of ridiculous evils. At the same time, though, it's capable of breathtaking goods. When I think about the future, those goods are what I focus on. Yes, the evils will happen - but why bother worrying about them too much? They'll pass.
Because the next evil might just be the one that kills you.
I think it helps to admit that you might die at any minute, and then throw that into a small, survival-geared part of your mind and go about living your life anyway. Fact of the matter is, a great deal of people live long and happy lives, and for most people live is pretty good. Too many bright people throw out the evidence of happiness to dwell on the bad.