Chapter 8      Part C 

The important point to be made about Bayesianism, as far as this book is concerned, however, is that the Bayesian model of the human mind is the one on which the rest of this book will be founded. For all of the further points that I argue in this book, I will try to show that they appear to have the best odds of working in the future, not that any one of them is logically inescapable. To aim for logically inescapable conclusions is to violate the spirit of Bayesianism, and to waste one’s time. In this life, any search for perfect confidence in any belief is either deluded or doomed to cycle after cycle of circularity, frustration, and failure.  

Therefore, we must aim to adopt beliefs that, when they are used to construct arguments, make our conclusions look more and more probable the more we check those conclusions against wider and wider bodies of observations of physical evidence. High and increasing levels of probability are what we want, probabilities that appear to keep climbing the more of the real world we explore.

Over two hundred years ago, David Hume spotted a major problem with the whole method of reasoning by induction, which is the reasoning method that empiricism and Science depend on. (2.) If we draw generalizations from our masses of experience of the real world, no matter how careful we are in how we observe reality, nor how careful we are in formulating our generalizations, nor how thorough we are in doing research to further test, refine, and bolster these generalizations, we are still not able to say with certainty that any of them is “true”. To do so would be to posit that the events of the future will be like the events of the past. We can posit that axiom only tentatively. We haven’t been to the future.

Bayesianism slips out of the problem of induction. It simply says that we are gambling all of the time, and we are checking our generalizations – even our most general ones, the ones that we need in order to see reality and form generalizations at all – against real world data constantly. By choosing to live in this state of permanent tentativeness, we are even gambling on alert, rational gambling as being our best gamble. 

But we aren’t putting all of our eggs in the single basket of any one model of any part of reality. Rationalists end in doing that, as they “reason” their way from sets of concepts that they “just know” to premises that they won’t question to policy decisions that they won’t analyze, no matter how ineffective or destructive the consequences of those policies may more and more appear to be.

With Bayesianism, we also aren’t stopping in our progress toward a kinder, wiser world in a sort of stymied funk, which is what we would do if we kept staring at the problem of induction and refused to get on with life until that problem was solved. It isn’t going to be solved. Bayesianism gives us a viable way out.

Thus, we can get on with it …the task of formulating a moral code based on our best current models of the real world. In the coming chapters, the Bayesian view of the human mind, combined with two of the most basic ideas in Physics and a model of cultural evolution, will enable us to build a modern moral system. And then, finally, we may be able to make a case for belief in the existence of God.

Notes 

2. http://plato.stanford.edu/entries/induction-problem/