I wasn't really sure which area to put this in, since it's kind of related to religion, but not entirely, and it can be related to politics in a way. I've been engaged in something lately that is really pointless, and that is arguing with post modernists. Now that pretty much includes a large portion of our society these days, but I had no idea how much ingrained post modernism is these days.
It seems that no matter what you try to argue and how well reasoned your argument is, someone is going to counter with, "That's true for you, but not for me", or "That's just your opinion." So the other day I brought up the law of non contradiction and the person responded with, "Well, that's YOUR opinion." So according to that line of thought, two people can make statements that are complete opposites and contradict each other completely, and each person can be right because it's all a matter of opinion.
It strikes me that before you can convince someone that something is true, you actually have to convince that person that there is a such thing as truth, that there are propositions that are intrinsically true regardless of shifting opinions. You can reason everything as well as can be, but getting around that problem can be extremely frustrating to say the least. The best response I have been able to come up with was when someone said, "There's no absolute truth!" and I asked if that statement was absolutely true. I only succeeded in confusing that person, but maybe that was a good start.
How does this tie in with politics? I'm not entirely sure, except for the fact that many people on the left are social liberals as well and most social liberals fall into this way of thinking. They have a post modern way of looking at issues such as abortion and gay rights, but mention something like tax policy and you will hear their positions defended as absolute truth. How do you even talk to these people? How do you reason with someone who says your conservative positions on social issues are all just a matter of opinion, but who will counter with an absolute belief in a punitive tax system? I guess all we can do is try to point out the inconsistencies of the left and hope the average Joe Schmoe is smart enough to see it.