In my article Inferring with Caution, I discussed the dangers inherent in basing one’s premises and assumptions on a priori arguments. An a priori argument is one in which a person’s conclusion is masked as a premise. In finer circles, it has come to be known as an argument that doesn’t pass the kosher test.

Two of the best examples of this are global warming and evolution. Global-warming fanatics love to make introductory statements such as, “The causal link between man-made emissions and global warming is well established.” Here’s a small excerpt from what journalist/author Melanie Phillips, Great Britain’s answer to John Stossel, has to say about such a priori arguments on her website:

“Wrong, wrong, wrong, and wrong. There is no such evidence. The whole thing is a global scam. There is no firm evidence that warming is happening; [and] even if it is, it is most likely to have natural, not man-made, causes. Carbon dioxide, supposedly the culprit, makes up such a tiny fraction of the atmosphere that even if it were to quadruple, the effect on climate would be negligible. And just about every one of the eco-doomster stories that curdle our blood every five minutes is either speculative, ahistorical, or scientifically illiterate.”

Her next line should have been, “Now, let me tell you what I really think.” Seriously, no one knows for certain whether man-made global warming is actually occurring. It very well may be … or it may not. All I can say about it is that the “facts” I’ve seen and heard are selectively attractive, at best.

Just to create a bit of excitement, I’ll weigh in on global-warming issues from time to time. It’s the easiest way I know of to get e-mail feedback. Or tarantulas in your mailbox. Or to lose thousands of subscribers who don’t like to read things that don’t fit into their existing belief systems.

As to evolution, it’s a topic that trumps such mundane subjects as gun control, abortion rights, and racial profiling when it comes to creating hysteria. Evolutionists are fond of beginning arguments with such statements as, “The debate over whether or not man got here through evolution is over. The facts are overwhelming. There is no more debate.”

To borrow from Ms. Phillips: No, no, no, and no. It’s not kosher to begin a debate about anything by announcing that the debate is over – implying that “everyone” already agrees with your position.

Again, as with global warming, there is no clear evidence – some would argue no evidence at all – that man evolved from a lower species. He very well may have … or he may not have. Either way, the jury is still out. Clearly, evolution within individual species has taken place over millennia, but the idea of one species evolving into another is very much open to debate.

All this is important, because the refusal to allow people to pass off their conclusions as premises for their viewpoints has serious ramifications in your day-to-day life. When it comes to negotiating, for example, accepting the other side’s use of an a priori argument as a starting point is a surefire loser every time out.

Challenging premises is an important life skill that you would do well to convert into an ingrained habit. Whenever I challenge what I believe to be an invalid premise – and I do it quite often – I’m amazed at how much better things seem to work out for me.