A mind is a program whose prime function is to calculate the usefulness of other programs for enhancing and perpetuating conditions that will preserve that mind and then produce more minds.

I am constantly calculating, usually as an unconscious activity, the odds that each of my familiar ways of organizing my thoughts, processing sense data, and formulating action plans is still working and is still adequate for interpreting and reacting to the physical situation that I am in at any given time. Once in a while, I calculate the odds that a different way of thinking, one that I am only considering using, will obtain good results—that is, happiness and health—for me, my children, and my nation over the long haul. The majority of the time, I check my sensory impressions against my expectations and reaffirm the beliefs and models of reality that have got me this far.

If I conclude that a new way of thinking about reality is an accurate one and that it will enable me to foresee pain and avoid that pain, or to find more pleasure, health, and vigor, then I tend to move aside some of my old mental gear and move the new ideas in. This is true of almost all the programs that my mind now contains. I become anxious and reluctant when some event or argument challenges my deepest and most general programs—my values. Those I will replace only in dire circumstances or after years of reprogramming. Once in a while, if I’m very stubborn in refusing to learn life’s latest lessons, I—or my family or even my tribe—will be discarded from the human community of the planet by evolution itself as some new, more efficient society replaces us.

That picture, I believe, is the best current description that I have of myself. (See also Hofstadter’s I Am a Strange Loop for a computer scientist’s interesting take on consciousness. A candid, enjoyable read.¹)

Bayesianism says of itself that as a model of how humans think, it is probably the best model. The odds that we should accept it as the best model of the human mind keep increasing the more that we use it, then handle reality well because we are using it. That is to say, the more we handle reality, individually and as communities, the better off we are compared with other humans using less flexible, less effective, less resourceful, less nimble models.

However, this description has an important caveat attached. If I’m honest, I‘m must admit that sometimes I am not capable of making my odds-weighing judgments astutely, especially when the judgments are about some of the mental gear that is most central in me. This gear includes the moral beliefs most widely connected to all the other systems in my mind.

I am very reluctant to change these central operating systems, which in plainer language are programs I use as I am deciding, second by second, item by item, for each possible reaction, “Good or not? React or not?” Those are the systems people are most reluctant to change. Because of cultural programming, deep emotions are associated with our values. Rather than change their moral values, many people prefer to die fighting to preserve those values, and in fact they sometimes do.

War is the harshest mechanism by which the values pool of the human race evolves—wars among nations, rather than rational persuasion among individuals. This is a mechanism that used to serve a purpose—it cut out of our species' total culture pool what no longer worked. But today, it is mental baggage we can no longer afford to carry. What it used to accomplish for our species we must learn to accomplish in other ways, if we are to survive. Our bombs have become too big.