Monday, February 20, 2017

The Mis-Measure of Human Rationality

The following is supposed to be a test of human rationality.
Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations. Which is most probable, that Linda is:
1. a bank teller;
2. a bank teller and a feminist.
Unless you state, unequivocally, that 1. is most probable, you are, so the scientists of the human mind insist, irrational.

Why? Because both 1. and 2. tell you that Linda is a bank teller, but 2. also tells you that Linda is a feminist, which may or may not be true. Therefore, whatever the truth of the claim that Linda is a bank teller, the claim that she is both a bank teller and a feminist less probably that that she is merely a bank teller.

Ha! were you fooled? Like, you thought Linda really was more likely than not to be a feminist since she's so into issues of discrimination and social justice.

So you're an idiot, right?

Or maybe not.

The Linda question asks people whose understanding of language depends on inductive inference, i.e., normal people, to evaluate statements as if they were taking an exam in formal logic, but without telling them that they are taking an exam in formal logic. Moreover, material is provided that is relevant to a common sense analysis, but irrelevant to a formal logical analysis.

The Linda question is, in other words, a trick question. And a silly one at that.

Consider: there is no connection whatever between the prolegamenon and the statements that follow it. The introductory material is included solely to mislead. It is there to elicit the false assumption (in the view of the questioner) that it is the basis for assessing the Statements 1. and 2.

But assessing propositions on the basis of whatever related information we may have is how the human mind normally functions, which is to say how it functions when it is serving as an adaptive mechanism to keep the human organism alive and well.

Moreover, in assessing the relative probability of Statements 1. and 2., the mind naturally focuses on the difference between the two, i.e., the question: is Linda a feminist or not?

That Statement 1. does not explicitly assert that Linda is not a feminist does not invalidate this common sense assessment, because common speech is not intended to conform to the requirements of formal logical analysis and is not interpreted as if it were: much of the meaning in human discourse is inferred or assumed.

Likewise, although there is no formal logical connection between Statements 1. and 2. and the introductory statements, there is no sense in the Linda question unless the introductory statements are assumed to have been provided as the basis for assessing which of the two statements, 1. or 2., is most probably true. Such assumptions are normal in human discourse, and without them human communication would be hopelessly long-winded, like listening to some maddeningly pedantic philosopher — Ludwig Wittgenstein, for example.

What that means is that people who are supposedly fooled by the Linda question are simply functioning as viable organisms, not desiccated logical analysts. Anyone who insists that the question should be assessed on the basis of formal logic is either ignorant of how intelligent organisms survive in the world or irrational.

The above remarks I made over at the Unz Review, a gathering ground for clever people who study the question of human intelligence. But then it seemed a waste to cast such pearls of wisdom, the fruits of my Darwinian mind, before an audience of g freaks and IQ fanatics whose entire system of thought is a perfect illustration of the fallacy of reification? Hence I decided to reproduced those comments here for the edification of a smarter audience.

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