An excellent way to learn clear thinking is to study the arguments taking place on the Internet. Yes, yes, I know, it’s all a stupid waste of time, a demolition derby of nitwits. But they do provide us with excellent lessons in faulty reasoning. I have for many years devoted a small amount of time — well, probably too much time — to discussing climate change on the Internet. Granted, none of these were actual discussions — the people who deny climate science are intellectual brick walls who are driven by political fanaticism, so no amount of logic or evidence will ever alter their beliefs. The only way they would change their minds would be if Donald Trump, Sean Hannity, and other conservative leaders were to announce that climate science is indeed correct.
We begin with a comment about climate change that contains three major faults:
The most obvious fault with this post is the meaningless vituperation, which is always poor argumentation. It convinces nobody. The second fault exemplifies misrepresentation of the evidence. It is the pair of statements inside the parentheses. Those statements are correct — but completely misleading. Here’s the actual data on sea level for the last 12,000 years.
On the left is sea level for the last 24,000 years; on the right is sea level rise for the last 115 years. The two graphs have dramatically different time scales, so I have added a red line to the left graph. That red line represents future sea level rise at 4.4 mm/year.
Thus, Mr. Woodward is correct in stating that “sea levels have been rising for 12,000 years”. The deceit lies in the fact that sea levels have been stable for the last 7,000 years. He is also correct in stating that “sea levels… are rising much much slower than they were during the real ‘melt’.” This, of course, does nothing to contravene the fact that sea levels are rising at a rate faster than at any time in the last 7,000 years.
The third fault in his argument lies in this sentence: “Do you have any idea how meaningless a ‘record’ that only reflect [sic] 100 years of measurement *at the very best* is?” His insinuation is that 100 years of data is insufficient to draw conclusions about the future. In the first place, the graph on the left demonstrates that our record goes back considerably further than 100 years. Indeed, we have enormous amounts of data about climate conditions going back hundreds of millions of years. In the second place, it is entirely possible to make extremely accurate predictions of future behavior from just a few observations over a short period of time — if one knows the underlying scientific principles governing the behavior, it is easy to make good predictions. While in high school, I built my own telescope and used it to gather data on the Galilean moons of Jupiter that permitted me to determine their orbital parameters and therefore predict future positions. A few years later, I showed undergraduate students how to use a larger telescope and a computer program to make even more accurate predictions. It all depends upon the scientific context. Mr. Woodward’s blanket statement that science cannot make reliable predictions is false.
It is a tribute to the combination of human creativity and human stupidity that there are a great many fallacies committed in argumentation. As always, Wikipedia has an excellent list of logical fallacies, but here are some more lists of common fallacies:
an e-Book about some fallacies
The right side panel of this page has a list of logical fallacies
A useful exercise is to plow through some Internet discussions of any controversial topic. I advise avoiding the more inflammatory topics, as these typically generate the most obviously stupid arguments from the most egregiously idiotic commentators. Evaluate the arguments proferred by the opposing factions. Almost all of the participants in discussion areas for the general public make scads of errors. For more subtle kinds of logical errors, you’ll need to track down some more intellectual sites.
