One might well ask why the very idea of selfhood - often the word 'ego' is used though it hardly fits the context - is so problematic for Buddhists? And if the sense of self is the root of all our problems, why do we even have it? Why did we evolve so unsatisfactory a faculty in the first place? I find the traditional answers to this question deeply unsatisfying and I know from talking to other Buddhists that I'm not alone in this. 
I've dealt with some of these questions in previous posts (see below) so here I want to look at where the sense of self comes from and why we have it. This is one area in which we need to quietly drop the tradition and find a better answer. I believe that neuroscience can provide a more satisfying answer to these kinds of questions, while leaving us the full scope of Buddhist practice as the best response the problems we encounter.
To my mind the best explanation for we we have a sense of self is put forward by Antonio Damasio in his book The Feeling of What Happens. Organisms, he says, are complex self-regulating mechanisms. Even a single cell is able to respond to changes in it's environment which allow it to survive better than if it were simply passive. So for instance if we are too hot we sweat, this fluid evaporates and this cools us down. This process has limits, but it enables us to tolerate a wide range of hot conditions, opening up ecological niches that might not be available otherwise. However sweating means we lose salt, and therefore we must ingest more salt. So the situation is complex and requires constant monitoring. In order to most successfully monitor our current state we need to compare a number of variables from the present (e.g. temperature, salt levels) with those in the past. Ideally we will have access to information about both the immediately preceding moment, but also to some longer term data which enables us to respond to trends in change. Even a single cell organism is able to monitor and adjust for such quantities as salinity, temperature, internal pressure, availability of food, light and dark, presence of predators, toxins, pathogens; and to do this without anything like sentience. We humans have a far bigger job. On top of each cell monitoring and regulating itself in concert with it's neighbours near and far, we have internal structures and systems such as organs; and we have an overview of the whole for maintaining things like balance, and readiness for action, and for the all important social interactions that we maintain. There is a vast, elaborate array of internal states at a variety of levels to keep track of. This is the primary function of our brain. We map all of this information in our minds - largely unconsciously - and keep track of it. This is the most rudimentary level of consciousness.
We also maintain archives of previous states: we can compare our present state to the immediate past so that we can respond to trends in the environment. If I am a little hotter now, but know that I'll be cooler again soon because it's late afternoon and the sun is getting low in the sky, then the need to cool my body is less urgent. Longer term memory enables us to understand trends and minor fluctuations better. But a consequence of this ability to compare our present state with many previous states is that we develop a sense of continuity. There is our map of our internal states now, and there are all these previous states. Demasio argues that the sense of continuity is an illusion. Consciousness is a series of discreet states of awareness, a snapshot of how we are now that can be compared with how we have been. This happens fast and often enough to give a sense of continuity - much like a film gives the illusion of motion by using 25 frames per second.
At some point in the evolution of this faculty the comparison of states begins to take in mental states. When it takes in the act of comparing then there is an element of self-awareness. We become aware of being aware, and because of the sense of continuity we have the feeling that there is a constant presence 'I' behind the observations and acting on them. However contra what most Buddhists say the 'I' naturally experiences itself as embedded in a complex web of relationships with the environment and other individuals. 'I' is not naturally alienated from these relationships.  Next week I'll look more at why 'I' has become alienated, and in two weeks will look at the 'I' as the basis for empathy.
This is not mere epiphenomenalism - the idea that consciousness is caused by the matter of the brain, and not the other way around - because it suggests that the demands of consciousness have driven the evolution of the brain. If anything the brain is an epiphenomenon of consciousness.
A further advance on this faculty is the ability to predict future states. This is the basis of imagination - the ability to project ourselves into the future and see if a course of action is fruitful, or if a situation is likely to be dangerous. It enables us to plan ahead, to predict the kind of impact the environment is going to have on us and to make preparations. It enables us to devise ways to overcome problems before they arise - by building a structure to keep the rain off before it comes, or planting crops that won't be harvested for several months, and to store food for winter or famine. Without the 'I' none of this would be possible.
The sense of being an embodied self, then, emerges naturally from the evolving faculties of the human organism, and it is important to our healthy functioning. However we are still left with the problem of suffering and what to do about it, which is the subject of next week's essay.
- Links to my other blog posts on ego.
- Ego Again [20.2.09]
- Anatta in Context [24.10.08]
- The Problem of Self-preoccupation [11.3.06]
- Ego in the Spiritual Life [4.3.06]