Desirism, "Should", and Reasons for Action that Exist

"Why should I do X?"

According to desirism, all questions of the form, "Why should I?" are asking for a reason for action that exists.

The phrase "that exists" appears because a lot of answers will refer to reasons for action that do not exist. A person might say, "Because God wants you to," or "Because it will help the garden spirits harvest stuff for their pet whatzits," or "Because it is a simple irreducible fact that you should do X." None of these reasons are real. Consequently, they do not provide an agent with a real reason to do anything. A real reason to do something must be a reason that exists.

Desires are the only reasons for action that exist. Therefore, any appeal to a reason for action that exists must be an appeal to desires.

Specifically, a desire is a propositional attitude that gives an agent a motivating reason to realize a state of affairs. A "desire that P" for any proposition P is a motivating reason to realize a state of affairs in which "P" is true. A desire that I am eating chocolate ice cream is a motivating reason to realize a state in which "I am eating chocolate ice cream" is true.

So, why should I do X?

Answer: Because you have a desire that P and doing X will realize a state of affairs S in which P is true.

At least, this is true for one sense of the word "should". "Should" is actually an ambiguous term - having multiple - but related - meanings. All of those meanings refer to reasons for action that exist. However, they look at different bundles of reasons for action.

The meaning that appears above shows up in a sentence like, "I should go to the gym tonight, but I want to get home and get logged in to my game." The agent has reasons for action that motivate him to go to the gym. However, he has more or stronger reasons for action that generate a stronger motivation to go home. There is a sense of the word "should" that isolates single or small bundles of desires and looks at the actions they recommend.

A second sense of the word "should" looks at all of an agent's desires. "I really should go to the gym," in this sense means, "If we consider all of my present and future desires, they would be better served by my going to the gym." One problem with this, however, is that future desires have no ability to motivate present action. Tomorrow's desire to eat chocolate cake cannot motivate today's behavior unless the agent has a present desire that the future desire be satisfied. Even here, it is the present desire that motivates behavior, not the future desire.

Consequently, an agent can know, "I really should go to the gym," and yet fail to go to the gym.

The set of reasons for action (desires) that exist is larger than the set of reasons for action (desires) that an agent has or will have. Your desires are reasons for action that exist. However, they are not reasons for action that I have. Your reasons for action that exist are not going to move me towards any course of action unless I have a desire that your desires be satisfied. This is true in the same way that your own future desires will not move you to act in a particular way without a present desire that your future desires be satisfied.

However, in both cases, there is a sense of the word "should" that refers to those external desires. There is a sense of the word "should" that says that there are reasons for action that exist for you to contribute to feeding the hungry. These reasons for action that exist include the desires of the hungry.

Making you aware of these reasons for action that exist will not, by itself, motivate you to act. I can say, "You should help to feed the hungry." You can respond by shrugging your shoulders and saying, "So what? I don't care to."

However, those same reasons for action that exist are reasons that others have to promote an interest in caring in you and others. Since praise, condemnation, reward, and punishment are tools for modifying these desires, those reasons for action that exist are many and strong reasons to praise (and otherwise reward) those who are charitable and condemn (and otherwise punish) those who are selfish.

While you may shrug your shoulders and say, "I do not care," you cannot change the fact that people generally have many and strong reasons to praise and reward those who care, and to condemn and punish those who do not.

This, then, is the moral sense of "should".

Consequently, there are three answers to the question, "Why should I do X?" that correspond to three definitions of "should".

Using the first meaning, the answer is because you have a desire that P and doing X will realize a state S where P is true.

Using the second meaning, the answer is because doing X will create a state of affairs that will objectively satisfy the most and strongest of your current and future desires.

Using the third meaning, because people generally have many and strong reasons to praise and reward those who do X and to condemn and punish those who do not. In other words, because it is the morally right thing to do.

In a second case, a person who has all of the relevant facts might still fail to do what he should. He may be aware f future desires. However, future desires have no ability to reach backward through time and influence present actions.

Similarly, a person may be aware that an action may be one that people generally have many and strong reasons to praise or condemn, yet still fail to do the right thing. This is because desires (reasons for action that exist) are incapable of jumping across brains. An agent needs a desire to do the right thing (understood as a desire to do that which people generally have any and strong reasons to praise and not do what people generally have many and strong reasons to condemn) . Even here,that desire can easily be outweighed by other interests.