This column was started several months ago in part from my frustration at seeing experts, particularly in medicine and politics, make wrong decisions based on good data combined with a faulty analysis. As time has progressed, I presented the essence of Bayesian decision theory, statistics, and probability combined with a healthy dose of puzzles and paradoxes. I tried to choose the puzzles to be fun and illustrate various aspects of critical thinking.
All this is good fun and games. However, the issues that I present are serious – deadly serious. If you are President on the USA and want to respond to 9/11, what do you do? If you are a devout believer in the religion of your parents and your advisor tells you that God wants you to blow yourself up and take along as many non-believers as possible, what is the probability that is a true message? How do you decide?
In short, I am saying that while solving handshake puzzles can be fun, the effort is ultimately useless unless the mental process you used to solve the artificial puzzle can be generalized to applications in the real world.
If a Fundamental Christian Minister tells you that abstinence from sexual activity is the safest way to avoid both VD and unwanted pregnancies, do you nod in agreement with the understanding that if you don’t have intercourse, then you are safe? Or do you evaluate abstinence as a method and only look at the results? If you do the latter, then the jury has already returned with a verdict: abstinence is the least reliable and most dangerous of the common methods of both birth control and control of STDs. That is, you cannot throw away data just because you don’t like it. If a moral value is presented as the solution to a physical problem, then the action is judged by the physical standards, not the moral ones. When abstinence fails and results in an unwanted birth, that is no different than the same results from a hole in a condom in the physical world. Would the Minister agree with that?
What’s the difference between news and propaganda? Is there a difference? Can we apply logic and decision theory to news sources or to religious teaching?
I took a lot of flack during the series on the difference between conjectures, hypotheses, and theories because I refuse to consider intelligent design to explain the diversity of life forms to be a theory. At best, it is a conjecture. Why shouldn’t we consider ID to be on the same intellectual level as Darwinian evolution?
By law our mass media must “present both sides” of controversies in a balanced way. When is an issue a controversy? Do all controversies have two sides of equal value? If someone advocates a return to slavery, are we obligated to hear both sides? Is the word of God sufficient reason to prevent same-sex marriages? If so, which God? If marriage was instituted by your God, what is the status of those who do not believe as you do?
Can logic and reasoning ever solve all the problems of philosophy and religion? That is an easy one; by iron-clad logic, the answer is “NO.” Any logical system that is interesting enough contains statements that are not probable within that system. So don’t think I am hitting on religion here. In fact, I am supporting the idea that we need belief systems. However, we should all work to make sure that our beliefs are at least self-consistent and do not contradict physical measurements. That is the essence of this series.
For those who wish to delve further into decision theory without wading through a lot of equations, I have posted a tutorial on elementary decision theory. It shows examples of faulty physicians’ diagnoses (important for those considering surgery) and how to evaluate anti-terrorist activities (important for everyone). That tutorial can be found here.