Toward a Post-Cartesian Theology, Interlude: Want to be more like Jesus? Drink a Coke.

I've been writing about how to do theology in the post-Cartesian situation. But what does this mean? A post to illustrate.

Rene Descartes (1596-1650) is the influential French philosopher who is the often credited as the modern exponent of what is known as Cartesian Dualism. Cartesian Dualism is the idea that mind/soul and matter/body are two distinct "substances" that interact with each other. However, mind/soul cannot be reduced to matter/body. This is the vision behind most theological systems, that we are dual creatures, a mixture of physical and spiritual attributes. We have a soul that interacts with our body but is distinct from our body. We are more than simply a body.

Cartesian Dualism, the view held by most church going folk, supports notions of immortality and free will. That is, it is assumed that our soul is immortal and that it is this attribute of the soul that guarantees that we will live forever (in either Heaven or Hell). Regarding free will, given that the soul is independent of our body, our choices (as products of the soul) cannot be reduced to cause & effect. Thus, we escape determinism and create notions of moral accountability.

So, what is the post-Cartesian situation? The post-Cartesian situation is the world of neuroscience and genetics. In our world it is difficult to believe in the existence of the soul when all known mental processes are directly correlated with brain function. Brain damage, intoxication, sleep deprivation, hunger, Alzheimer's disease and many other factors clearly demonstrate that as our brain goes so we go. And, if this is so, how should theology respond?

I've been arguing that theology needs to work with what I've called weak-volitional models. That is, we need to see our choices (products of will/volititon) as contingent. I don't know if our choices are determined. But I do think they are highly contingent. That is, the circumstances of our lives affect the outcomes of our choices. More specifically, for today's post, the status of our brain can affect the outcomes of our choices.

In a recent study published in the prestigious Journal of Personality and Social Psychology the psychologists Matthew Gailliot, Roy Baumeister, Nathan DeWall, Jon Maner, Ashby Plant, Dianne Tice, Lauren Brewer, and Brandon Schmeichel examined the role of glucose levels in the exercise of self-control. The study was entitled Self-Control Relies on Glucose as a Limited Energy Source: Willpower is More than a Metaphor.

Baumeister has done lots of work on the idea that self-control (ego-strength) is a finite and limited resource. Across many laboratory studies Baumeister has demonstrated ego-depletion. That is, if you are asked to expend mental energy (e.g., acts of self-control, concentration, or attention) you show a reduced capacity for self-control, attention or concentration on subsequent tasks. That is, mental "energy" seems finite. Thus, if you "use up" your mental energy on one task you have less energy available for later tasks.

We all know this don't we? Ask yourself, when are you most susceptible to outbursts of bad tempter (a failure of self-control)? Well, if you are like me it is when you are tired, stressed, or hungry. When my mental energy is low I just don't have much left over to regulate my irritability.

But in the Gailliot et al. study ego-depletion is given a biological mechanism. Glucose.

Restating, you don't have an unlimited supply of willpower. Willpower is not a product of the soul which can tap into an infinite supply of supernatural fuel. No, in the post-Cartesian situation we know that willpower is the product of the brain and that the brain, as an energy consuming organ, has a limited capacity. As the title of the study highlights, willpower is more than just a metaphor. Willpower is, actually, power which can be consumed and used up.

For example, we know these things. The brain consumes 20% of the body's fuel while comprising only 2% of the body's mass. We also know that glucose is a vital fuel for the brain. And we also know that low glucose levels have been implicated in impulse-control problems. Could there be a link between willpower and glucose levels in the brain?

In a series of eight studies, Gailliot et al. demonstrate that low glucose levels are related to impairments in self-control. Further, elevating glucose levels (via a sugary drink) aided participants in self-control compared to control subjects.

Importantly for theologians, two of the self-control tasks directly involved social virtue: Controlling prejudice in an interracial interaction and helping someone in need.

Now think about that. When your glucose levels are low you are more susceptible to acting on prejudice and less helpful to strangers. When your glucose levels are normal you are more able to suppress prejudice and more likely to help strangers. In short, your virtue is directly affected by sugar levels in your brain. Quoting from the final paragraph of the study:

"The present findings suggest that relatively small acts of self-control are sufficient to deplete the available supply of glucose, thereby impairing the control of thought and behavior, at least until the body can retrieve more glucose from its stores or ingest more calories. More generally, the body's variable ability to mobilize glucose may be an important determinant of people's capacity to live up to their ideals, pursue their goals, and realize their virtues."

So, this week in my Sunday School class at church I'm going to make the following recommendation: If you want to be more like Jesus drink a Coke.

But make sure it's not diet. You want the sugar in there.