On Desire 2018. Part 24: Manifestation-Dependent Desires vs. Motivational Force

Maria Alvarez, (2017), “Desires, Dispositions and the Explanation of Action” In Deonna J. & Lauria F. (eds). The Nature of Desire. Oxford University Press

Desires are manifestation-dependent, according to Maria Alvarez.

Ultimately, I am going to have to reject Alvarez' thesis. But, first, let's try to understand it.

On the dispositional view of desires, a desire is a disposition to act in a particular way under particular circumstances. Desires are often compared to traits such as solubility (a disposition to dissolve when placed in water), or fragility (the disposition to shatter when struck). The aversion to pain, then, is a tendency to wince and cry out when burned, or to take actions that would prevent being burned in the first place.

Alvarez goes into some detail on the types of manifestations that accompany desires. A desire's manifestations include not only a disposition to act in particular ways (e.g., to avoid states in which one is in pain), but also to have certain emotions (fear, hope, joy), and certain thoughts (fantasies) relating to the object of desire.

However, she denies that there is such a thing as a desire that does not manifest itself in some way or other. A desire that never manifests itself in some way, never exists.

In this, desires are different from other dispositional states. A lump of salt can be soluble even if it never actually dissolves in water. It can stay in its rock form for all time, and yet it remains soluble. Similarly, a fragile thing might be fortunate enough never to have been struck and, thus, remain unbroken. Yet, it is still fragile - likely to shatter when struck.

Let me put this into the context of this general discussion of desires.

I have been arguing against (1) the doxastic theory of desires (a "desire that P" is a belief that P is good), (2) the perceptual theory of desire (a "desire that P" is a perception that P is good), and (3) the dispositional theory of desire (a "desire that P" is a disposition to act in certain ways). Instead, I have been arguing for what I have called an assignment theory of desire (a "desire that P" is an assignment of importance to P being made or kept true).

So, this is a conflict between the dispositional theory and the assignment theory. Alvarez is offering a refinement of the dispositional theory by saying that a desire that does not manifest itself (that does not actualize at least one disposition) does not exist. Desires are, in short, manifestation-dependent dispositional states.

In considering Alvarez' thesis, I find it interesting to compare this dispositional view of desire with the force view of desire.

We often do speak of desires as if they are forces. For example, the phrase "motivational force" is quite common. I have not thought of the force model as being in conflict with the dispositional model before. Yet, the force model seems to make more sense of the problems that Alvarez recognizes in the dispositional model, without creating more problems of its own. Plus, the force model is compatible with the evaluationist model of a "desire that P" as an assignment of a value (importance) to a proposition P being made or kept true. The assignment of such a value - the assignment of an importance - is directly related to the motivational force of the desire. The more important it is that P is made or kept true, the stronger the motivational force.

Consider the possibility of a force that never manifests itself. For example, the universe could contain a force F0 such that, any time F0 acts on an object its counterpart, F1, also acts on the same object. F1 is related to F0 in that it always goes in the opposite direction at exactly the same magnitude at F0. Consequently, F0 (and F1) never manifest themselves in any observation. They never contribute to the acceleration of any object since the effect of one is automatically cancelled out by the force of another.

We can ask a further set of questions: Is it the case that such a force (or pair of forces) exists and we cannot know about it? Or is it the case that this pair of forces does not exist? And how can we tell the difference? And what does not matter?

These are the same questions we can ask about a desire that never manifests itself. Does such a desire exist even though we do not know about it? Or is it the case that such a desire does not exist? And how can we tell the difference? And does it matter?

It is clearly the case that we have no reason to postulate the existence of such an entity. We postulate forces - such as gravity, electro-magnetic, and strong and weak nuclear forces to explain and predict what we see happening in the world around us. The F0/F1 pair does not explain or predict anything in the world around us. So, ultimately, we easily arrive at an answer to one of our questions - the possibility of an F1/F0 pair of forces does not matter. I am willing to go further and say that the F0/F1 force pair does not exist. This is because, for all practical purposes, it does not exist, and that language is, ultimately, a tool invented to serve a practical purpose. That which does not exist for all practical purposes does not exist (for all practical purposes).

We postulate desire to explain and predict intentional action. If we have no intentional action to explain, then we have no reason to postulate the existence of a desire. Such a desire does not exist for all practical purposes, which means that I am willing to allow that such a desire does not exist.

We seem to have something here that corresponds to Alvarez' thesis - a desire that does not manifest itself in any way does not exist. However, I did not get to this conclusion using the view that desires are dispositional states. I got here using the idea that desires are like forces - where a desire that P assigns an importance to P being made or kept true. An assignment of an importance to P being made or kept true does not exist - or, we have no reason to postulate the existence of such a desire - if it does not help us to explain or predict intentional behavior.