The public debate about same-sex marriage has raised some really interesting questions about the nature and rationale of marriage. Marriage is an institution which we observe across space and time, but why do we have marriage and why has it been so prevalent across societies? Marriage in the West has been eroded over the past number of decades and many see the extension of the marriage franchise to same-sex couples as a further weakening of the institution. Unfortunately, much of the debate on this issue is being stifled and sometimes there is more heat than light. However, I recently came across a really good debate on Piers Morgan's CNN show, which featured Ryan Anderson of the Heritage Foundation, a conservative think tank based in the United States.
The Berkeley Earth Project , an independent study of global warming, has found that the earth has become a degree warmer over the past half century. However, the statistical uncertainty surrounding pre-1920 estimates makes it very hard to say much about long-term trends - click here for graph . This is one of my concerns with the global warming debate - we simply don't have trustworthy long-run data which looks at temperature changes over the last millennium (or two). My second concern with the global warming debate is that it is very hard to prove any sort of casual link between global warming and human activity. The scientists may be able to show correlation between global warming and our production of carbon dioxides etc., but correlation is not causation. My third concern with the debate is that those who are sceptical or agnostic are stereotyped as flat-earthers or intellectually-challenged crackpots. This only stifles debate and the progress of science itself.