Or maybe it's just optimism and the belief that society tends towards increasingly more rational behaviour. Unless there are some dramatic scientific findings in the future, the case against cannabis is flimsy at best -- especially when compared with other legal drugs like alcohol and tobacco.
By any reasonable account, things have been getting better for at least several centuries now. Infant mortality is down, birth rates drop as prosperity increases, advances in farming technology have rendered world hunger a logistics problem, literacy rates are improving and access to education (traditional or otherwise) has never been better. Fewer people are being burned as witches (particularly in developed and developing countries). Entire diseases have been eradicated and more will soon be eradicated. Tolerance of alternative lifestyles, once relegated to small pockets of geography and history, is spreading. Slavery continues to be on the decline.
The collapse of the Roman Empire was by most accounts a setback, as was the the Black Death and two brutal world wars (though even after those we resisted the temptation of widespread nuclear, chemical or biological warfare). It really is quite difficult to find broadly negative trends. Even the loss of the Roman Empire becomes a temporary setback if you zoom your timeline out more. The Romans were doing better then the Babylonians (well, some of them were at least), and we are doing better than they were at their height.
Things get better because that is what humans do; we stand on the shoulders of giants. Stubborn incremental improvement.
I like the way you think, the cut of your jib, etc. That's how I view open source – as a culmination of millennias-worth of incremental changes and improvements.
