Monday, June 11, 2018

On Desire 2018. Part 35: The Logic of Preference and Desire

I was wrong.

Remember when I said that an aversion was a negative desire? I am certain that, if you look around, you will find a number of instances in which I said that an aversion to P was the equivalent to a desire that not-P.

That is not entirely accurate.

Are you familiar with the “pain scale chart”? The most common version asks a patient to rank his pain on a scale from 0 (no pain) to 10 (GOD, KILL ME! I CAN’T TAKE IT ANY MORE!!).

I am going to use negative numbers in what follows because I fear that using positive numbers for pain will be confusing.

Let’s say that you have a pain of -8. This is pretty bad pain, but I am no sadist. I could go higher, but I won’t. I just need you to be in enough assumed pain to allow me to make a point.

If we apply “An aversion to P is equivalent to a desire that not-P”, this means that not being in pain has a value of 8. Right? If an aversion to a particular pain is at -8 then this is equivalent to saying that you have a desire for not-pain or no-pain of 8. You would likely go to a lot of effort to get to a state of no pain, and this amount of effort is equivalent to the effort you would go through to fulfill a desire that has 8 points of positive value.

But . . . look at that pain chart again. “No pain “ has a value of 0. The state of affairs in which you are not in pain has no value.

0 does not equal 8 - at least on the mathematical systems I am familiar with.

We have a contradiction.

Contradictions are bad.

This contradiction exists because we made a false assumption; the assumption that an aversion to P is equivalent to a desire that not-P.

"We" made this mistake because I am not taking the heat for this by myself. I am taking you with me.

To show that this assumption is a mistake, let us put you back in a state of pain. Now that you are in pain, I'll let you know that I can give you a shot. This shot will reduce the amount of pain you experience from -8 to -2. It won't get rid of the pain, but you will definitely be a lot more comfortable.

See, I told you that I was no sadist.

Do you want me to give you the shot?

I am going to guess that you will.

Does this mean that you desire a pain of -2?

No! Of course not! You have an aversion to a pain of -2 - though not so nearly as much of an aversion as you have to a pain of -8. A pain of -2 is preferable to a pain of -8, but it isn't good. It isn't desired. It's just preferred.

And therein lies the source of our problem.

The term "desire" is ambiguous. There is an absolute value sense of desire (the sense in which you assign of value of -2 to the pain that you experience after getting the shot), and there is a comparative sense of desire (how a pain of -2 stacks up when compared to a pain of -8).

The thing is that we have a different word for the comparative sense of desire. We call it a "preference".

"No pain" has a desire value of 0. However, when compared to a pain of -8, "no pain" has a preference value of 8.

Olivier Massin wrote that a person with a desire to smoke cannot be indifferent to not smoking. (Massin, Olivier, (2017), “Desires, Values, and Norms” In Deonna J. & Lauria F. (eds). The Nature of Desire. Oxford University Press.)

When not smoking is compared to smoking, and the agent has a desire to smoke, this is true. When comparing the two, the person with a desire to smoke is going to prefer smoking to not smoking. But to prefer not smoking is not to say that not smoking has positive value. There are a great many not-smokers out there who assign no positive value to smoking whatsoever, and our agent might well long to be one of those people.

I might be tempted to say that the comparison sense of desire is the true and correct definition of desire, and thus I was right all along. Unfortunately, you can't have a comparison sense of some term unless there is something out there that you are comparing. We already have a perfectly good word for the comparison sense of desire. It is called a "preference". And, when one looks at the fact that it is nonsense to say that you would desire a pain level of -2 when, in fact, you would prefer it, we see evidence that we have a perfectly sensible term for the value assignment sense of desire as well. That is called "desire".

Now, we get to the point where I try to claim that I was actually right all the time. I was just misunderstood. There is a sense in which "an aversion is a negative desire" is true. That is to say, an aversion is a desire with a negative number - a desire that assigns a negative value to a proposition being true. In this sense, yes, an aversion is a negative desire - a desire that assigns a negative value.

If only I could honestly say that this is what I always meant every time I said that an aversion is a negative desire, I would be safe.

But, I don't think I can say that. I think that the fact is that I sometimes made the same mistake that Massin made in his article - a mistake in confusing the assignment sense of desire with the comparative sense of desire, and equivocating on some claims that I have said about desire.

Now that I cleared this up, I need to get back to Massin's article and explain what this implies about his "guise of the ought" thesis.

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