Al Gore's "An Inconvenient Truth" was quite a good documentary. Gore is a compelling speaker and very convincing. However, having listened to both sides of this global warming, or climate change, or whatever the PC term for it is these days, issue, it really points up to me how very difficult it is to know truth. Both sides make compelling cases, so who are we to believe? It is of great interest to me how two people can look at the same evidence, or read the same document, and reach almost entirely opposite conclusions. We see it in the philosophical realm, the religious realm, and yes, even the scientific realm. Most of the differing conclusions come from the fact that each person has his/her own level of evidence that is required to become compelling in his/her own mind. Since we rarely have the evidence required to be 100% certain of most things of import, we see greatly varied opinions. In many cases the actual truth lies somewhere between the most ardent believer and the most ardent skeptic.