Does a lack of energy make you not want to do anything? I say (with a few exceptions) it's the other way around. Not wanting to do anything makes you feel a lack of energy. I would also argue that when you do act it's not because you feel energized, you feel energized when your brain has been roused to action.
A little context: in the past few blogs, I have looked at the basic components of mental life, and specifically at the brain's capacity to rouse itself not only to stay awake and alert, but also to mobilize for action. The experience of mental fatigue illustrates how these arousal systems can go wrong and produce mental problems.
What is fatigue? Let's start with the forms of fatigue that truly arise from some bodily state. There are some forms of pathological fatigue, such as myasthenia gravis, in which the sense of having to force extra effort to act arises from some medical problem in muscle or nervous system physiology, such as a neurotransmitter deficiency. But most of us are more familiar with the fatigue that follows exertion, when muscles resist action because they lack fuel, and it takes time and food and water and oxygen to reset the metabolic mechanisms. Sleepiness is a form of fatigue that combines this refractory state with hormonal signals to shut one's eyes and rest.
Mental disorders might produce some of these states of fatigue indirectly through the loss of muscular tone that follows long inactivity or from malnutrition, both of which might occur from mental illness, such as an episode of depression. But this begs the question: what produces this feeling of inertia that consigns someone to the couch and saps the will even to get up and make a healthy meal?
Mental fatigue comes with little or no exertion; it comes when our desires are too weak to rouse us to action. Normal fatigue makes one want to rest, which is satisfying because it restores the energy in both mental and bodily aspects. Mental fatigue frustrates a person because the pursuit of rest it inspires fails to accomplish its goal; repose serves no purpose. And yet there is no arousal of interest to do anything else.
Now, if one could live without having to do anything, the feeling of fatigue might not feel so bad, but of course one has to get up sometime. If you are lacking in a desire to be clean, well fed, or socially presentable, you will find it harder to move yourself to get up out of bed to shower or eat or dress. But if you must get up and get going, the impetus will have to come not from any desire to do so, but from the sense of alarm or disgust at what would happen if you didn't. You might lose your job and disappoint people who depend on you. Thus a person lacking energy describes mundane necessities of daily living as a series of grim struggles to "push" to get things done.
If you're lucky, you have never had the experience of lacking any desire to keep up your health or hygiene or social life. Your feeling of fatigue is fleeting-you don't feel like doing something you need to do so you either put it off and go surf the net for awhile or you force yourself to do it-and more likely than not, if you do, you're glad you made the effort.
In a future blog entry, I'll get to the question of how one can lose one's desire to do anything. But first we should spend a bit more time on the basics. Next time I'll talk about problems that arise from having too much energy.
