Tag Archives: fallacy

The base rate fallacy

Amongst my favorite fallacies lies the base rate fallacy.

Here’s a great introduction to this fallacy on the BBC’s website.

Imagine you’ve invented a machine to detect terrorists. It’s good, about 90% accurate. You sit back with pride and think of the terrorists trembling.

You’re in the Houses of Parliament demonstrating the device to MPs when you receive urgent information from MI5 that a potential attacker is in the building. Security teams seal every exit and all 3,000 people inside are rounded up to be tested.

The first 30 pass. Then, dramatically, a man in a mac fails. Police pounce, guns point.

How sure are you that this person is a terrorist?
A. 90%
B. 10%
C. 0.3%

Income redistribution is ok because it’s already done?

» I Voted for Barack Obama on Blueprint for Financial Prosperity

As for the big focus on “wealth redistribution?” We’ve been doing it for years, it’s called the progressive tax system. While it seems like you’re punishing success and being a bit socialist, the alternative is far worse. Imagine a nation where there is an upper class and a very large lower class with few economic opportunities, filled with anger, desperation, and despair, and with very few options. Not pretty huh? America is still the land of opportunity, even if success is taxed a little more.

The above quote is taken from a blog about personal finance that I enjoy following. Can you see the logical fallacy contained within? I’ll give you a minute…


Ok, time is up.

Apparently, the author is attempting to say “Don’t worry about income redistribution because it’s already being done.” This is a mashing up of several logical fallacies.

Let’s say that you are of the opinion that income redistribution of the type we already have (progressive tax system), is a good thing. It doesn’t automatically follow that another type, or more, or less is also a good thing.