Introducing the Butler: Probability is the Very Guide of Life

by PDS

Joseph Butler was a philosopher and theologian from the mid 18th Century. His most important works, The Analogy of Religion and Fifteen sermons preached at the Rolls Chapel, have become lasting contributions to Philosophy of Religion, and Ethics. Both works are written from a distinctly Christian point of view, but are read by philosophers of diverse religions persuasions today.

Many of the posts in this blog will be focused on Butler’s works, as I believe his ideas deserve serious thought and study. This post will focus on the introduction of Butler’s Analogy of Religion: I will start to describe Butler’s methodology, his theory of knowledge, which under-girds the rest of the book. And as we have already touched upon some of the ideas of Plato, Aristotle, and Descartes we can read Butler with these thinkers in mind. Hopefully, this will make some of the terminology a little easier to understand.

The Analogy of Religion is an ambitious and methodical defence of Christianity. I will begin, as mentioned above, by sketching Butler’s approach, which he presents in his Introduction.

Demonstrative and Probable evidence

PROBABLE evidence is essentially distinguished from demonstrative by this, that it admits of degrees; and of all variety of them, from the highest moral certainty, to the very lowest presumption.”

Recalling Aristotle, a Demonstration is an argument with premises that are true and a conclusion that must follow if the argument is valid. A demonstration yields certainty.

Butler distinguishes demonstrative evidence from probable evidence, which gives us degrees of certainty; from the highest certainty – similar to a demonstration – to the lowest “presumption”, as Butler puts it. Probable evidence that gives a person slight presumption does not allow a person to say that something is probably true as there could be equally probable evidence on the other side of the equation. Saying something is probably true, therefore, requires a certain level of probable evidence.

Butler gives the example of observing the tide. One observation gives us a very low presumption that a similar event will happen again the next day; however, many months, or even years of observation will give us a high degree of probable evidence and, therefore, a high degree of certitude.

That which chiefly constitutes Probability is expressed in the word Likely, i. e. like some truth, or true event

When we make a judgement about whether an event has happened or will happen, we reflect on other similar events which we have certain knowledge of ie that we know have happened. The higher degree of similarity between the known events and the events we are making judgements about, the higher degree of certainty we can have in our judgements. The same applies to judgements about truths. Past observations then for Butler, provide us with the material to make judgements.

Only “an infinite Intelligence” can make perfect judgements about all things. For us, according to Butler, “probability is the very guide of life“. The fact, for example, that we know that food is necessary for healthy living is from past observations. And a great deal of the judgements we make in life are of this probabilistic nature.

Low Probabilities and Speculative Knowledge

Even when a judgement is based on low probabilities, according to Butler, we should still act. Even when there is a high degree of doubt in our minds. And this applies to both speculative knowledge, as well as in practical matters. What is the difference? Speculative knowledge is of being, while practical matters are about how we should act in the world. Speculating, therefore – as I understand it – is about reflecting on the nature of reality. And this reflection would include questions about God, the afterlife, the nature of a human being, and many other things.

Probabilities, for Butler, lay us under an obligation to act on what we judge to be true, just as much as when we have demonstrative evidence. He further notes the following:

in questions of great consequence, a reasonable man will think it concerns him to remark lower probabilities and presumptions than these; such as amount to no more than showing one side of a question to be as supposable and credible as the other: nay, such as but amount to much less even than this. For numberless instances might be mentioned respecting the common pursuits of life, where a man would be thought, in a literal sense, distracted, who would not act, and with great application too, not only upon an even chance, but upon much less, and where the probability or chance was greatly against his succeeding.

Butler reflects on how we act in life(and are even obligated to) when there are very low probabilities of success, especially when the judgements are related to very important issues. This point will be further explored in a later post.

At this point Butler draws his discussion of probability, and analogical reasoning to a close:

It is not my design to inquire further into the nature, the foundation, and measure of probability; or whence it proceeds that likeness should beget that presumption, opinion, and full conviction, which the human mind is formed to receive from it, and which it does necessarily produce in every one; or to guard against the errors, to which reasoning from analogy is liable.

This sort of reasoning, continues Butler, “is evidently natural, just, and conclusive“.

Next time we shall see how Butler intends to employ analogical reasoning to questions of God and religion as we continue to work though his Introduction.

What are the weaknesses and strengthens of analogical reasoning?