Category: Philosophy

The Trolley Car Approach to Public Policy

Scott Alexander has an article at Slate Star Codex discussing the use of edge cases in moral philosophy:

There’s a tradition at least as old as Kant of investigating philosophical dilemmas by appealing to our intuitions about extreme cases. Kant, remember, proposed that it was always wrong to lie. A contemporary of his, Benjamin Constant, made the following objection: suppose a murderer is at the door and wants to know where your friend is so he can murder her. If you say nothing, the murderer will get angry and kill you; if you tell the truth he will find and kill your friend; if you lie, he will go on a wild goose chase and give you time to call the police. Lying doesn’t sound so immoral now, does it?

This is a great way of doing philosophy, but reading it, I realized I had heard it before. I’ve heard this sort of argument in the context of policy debates.

Here’s a particularly striking example (h/t to Jason Brennan):

abolish_capitalism

Unlike the case of the door-to-door murderer, which is a deliberately fanciful way of examining a broader moral truth, this is a policy proposal made on the basis of a fanciful scenario. The argumentation goes like this:

  1. In an unlikely scenario, economic system A would allow bad outcome X
  2. Therefore, abolish A (and substitute it with another system, such as B)

There are a lot of errors packed into this line of thinking. What if bad outcome X happens under both systems? What if changing systems just substitutes bad outcome Y for X? What this fails to do is compare the relevant alternatives. Is the implicit claim that under socialism, nobody would ever starve? Millions of Soviet citizens beg to differ. (more…)

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Is a Small Amount of Money More Valuable to a Low Income Person than to a High Income Person?

street_beggar

I answered this question over at Quora. Just about all the other answers were wrong, so I thought I’d set things straight.

No. Value is not a quantity. It cannot be compared across individuals, so we cannot say that $50 is more valuable to person A than to person B.

To understand value, you must understand action. To act is to select one thing and set aside another. Thus, an ability to evaluate one thing over another is a necessary prerequisite to action, one that all mentally functioning humans possess. Valuation is always a comparison between two alternatives. It is a comparison made in the mind of an acting human.

Because the high income person and the low income person are different individuals, their valuations cannot be compared. We could say something like, “the low income person values an hour of his time less than $50, while the high income person values an hour of his time more than $50.” But this does not mean the low income person values $50 more than the high income person does in any absolute sense, because an hour of time is not the same to different individuals.

Some people have said that the answer is yes because marginal utility decreases with quantity. This is a misinterpretation. It is true that people tend to value additional units of a stock of interchangeable consumer goods less with each additional unit. This is because a person will use the first unit of the good to satisfy his highest unmet need, the second unit to satisfy his second highest unmet need, the third unit to satisfy his third highest unmet need, and so on. Thus, marginal utility does decrease with quantity. But it only meaningfully decreases with respect to other goods! If I have five dumplings, I might value an additional dumpling more than a battery, but if I have six or more dumplings I might value the battery more than an additional dumpling.

While I value things less with each additional unit, we can’t take this to mean my valuation of my total wealth must decrease as I grow wealthier. Total wealth comprises everything, leaving nothing to compare it against, so valuation is meaningless.

UPDATE: To clarify, if the question had been, “Would a gift of $50 improve the well-being of a poor person more than it would improve the well-being of a rich person,” then other people’s interpretations would be acceptable. The primary error is in using the word “value” without recognizing that value is a purely ordinal concept that has no interpretation outside the mind of the person doing the evaluating. “He would choose A over B,” is an identical statement to “he values A over B.” But neither of those statements are equivalent to “A would improve his well-being more than B” because sometimes people choose to sacrifice their well-being to achieve other ends. Think of soldiers volunteering for suicide missions.

The post Is a Small Amount of Money More Valuable to a Low Income Person than to a High Income Person? appeared first on The Economics Detective.

Is a Small Amount of Money More Valuable to a Low Income Person than to a High Income Person?

I answered this question over at Quora. Just about all the other answers were wrong, so I thought I’d set things straight.

No. Value is not a quantity. It cannot be compared across individuals, so we cannot say that $50 is more valuable to person A than to person B.

To understand value, you must understand action. To act is to select one thing and set aside another. Thus, an ability to evaluate one thing over another is a necessary prerequisite to action, one that all mentally functioning humans possess. Valuation is always a comparison between two alternatives. It is a comparison made in the mind of an acting human.

Because the high income person and the low income person are different individuals, their valuations cannot be compared. We could say something like, “the low income person values an hour of his time less than $50, while the high income person values an hour of his time more than $50.” But this does not mean the low income person values $50 more than the high income person does in any absolute sense, because an hour of time is not the same to different individuals.

Some people have said that the answer is yes because marginal utility decreases with quantity. This is a misinterpretation. It is true that people tend to value additional units of a stock of interchangeable consumer goods less with each additional unit. This is because a person will use the first unit of the good to satisfy his highest unmet need, the second unit to satisfy his second highest unmet need, the third unit to satisfy his third highest unmet need, and so on. Thus, marginal utility does decrease with quantity. But it only meaningfully decreases with respect to other goods! If I have five dumplings, I might value an additional dumpling more than a battery, but if I have six or more dumplings I might value the battery more than an additional dumpling.

While I value things less with each additional unit, we can’t take this to mean my valuation of my total wealth must decrease as I grow wealthier. Total wealth comprises everything, leaving nothing to compare it against, so valuation is meaningless.

(more…)

The post Is a Small Amount of Money More Valuable to a Low Income Person than to a High Income Person? appeared first on The Economics Detective.