# Belief As Probability Estimation

Belief is another way of describing an estimate of the probability of truth.

Facts about the world are sometimes clearly true or false.  These clear cut cases tend to be the less interesting aspects of the world. They are the dependable facts of the world like Newtonian Physics.

Yet science and materialist philosophy wants to deal in these “facts” and dismiss all else as belief and, worse “speculation”.

Everything in between may or may not be known true or false, but is not an undifferentiated grey zone. The likelihood of truth is probability from 0 to 100%. Some speculation is clearly very low probability and some is close, but not quite certain.

Sometimes this kind of probability can be analyzed mathematically, as when flipping a coin or playing cards. I know that flipping a coin gives me a 50% chance of heads and a 50% chance of tails. If my chances of getting on a plane depended on a coin flip I’d be complete unsure as to whether or not I’ll be leaving town. But if it depended on my drawing the King of Hearts from a deck of cards, I’d believe I was very unlikely to get on the plane.

Of course, more often its a complex state of affairs that makes me doubt I’ll be flying. I’m late in leaving for the airport and there are traffic and weather factors that can be known pretty well, but can’t let me be sure about whether I’ll be getting to the airport with enough time to get on the plane.

These statements about belief regarding a future state of the world are critical for deciding. Do we believe that the stock market will be higher next year than now?

More often when discussing belief, its more commonly stated in the present. Do we think its raining now? Do we believe that vitamin C is good for treating colds? Do we think the new drug can improve memory in patients with Alzheimer’s disease? Or the past- do we believe that Barack Obaama was born in the US?

Interesting, most of these questions of belief are important in the present because of how they will affect our present actions. And those present actions reflect choices that are aimed at influencing future states of the world. If I believe its raining, I will choose to take an umbrella. The truth of whether its raining will result in either my being happy I’m dry or unhappy that I’m dragging around an umbrella. I believe its likely the drug will be a blockbuster; I invest millions.

To me, it doesn’t matter whether we grab that umbrella without thinking or after 15 minutes of consulting internet weather sites and considering the burden of various umbrella choices in the event that it does or does not rain. Instinctive decisions or analytic decisions are based on beliefs that are probabilistic statements about the past, present and future.

Uncertainty in the world is way too complicated to submit to constant rigorous analysis. And too much analysis costs time and effort. But fortunately our brains are great estimators of probability- what we call belief. By honing the sense of probability, we probably can become better deciders through having more practical sets of beliefs: understanding the world and adjusting our beliefs to be more accurate, more predictive.

James Vornov