March 21, 2018

## Truth and pragmatics

We make decisions.  That’s a good part of what we do.  For example, I have just decided to compose a post about decision making.

But how do we make decisions?  How do we decide?

Generally speaking, we make some decisions on the basis of what is true.  And we make other decisions on the basis of what works best for us.  That latter kind of decision is usually said to be a pragmatic choice.

### Examples

If I am solving a mathematical problem such as balancing my checkbook, then I am making decisions based on truth.  If I am working on a logic problem, again that is going to be making decisions based on truth.

I walk into a restaurant, look at the menu, and decide what to order.  That’s normally a pragmatic choice.  It need not be.  Perhaps I have created a rule for myself that if it is Sunday I should order the first item on the menu, if it is Monday I should order the second item, etc.  If I am exactly following those rules, then I am making a decision based on truth.  But that isn’t what we normally do when ordering a meal at a restaurant.

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March 14, 2018

## Does consciousness exist?

To answer the title question, of course consciousness exists.

Galen Strawson has an article in the New York Review of Books (h/t Brian Leiter):

I doubt that I am on Strawson’s list of deniers, but perhaps only because he doesn’t know who I am.

What is the silliest claim ever made? The competition is fierce, but I think the answer is easy. Some people have denied the existence of consciousness: conscious experience, the subjective character of experience, the “what-it-is-like” of experience.

Given that introduction, I would probably fit right in with Strawson’s deniers.

March 11, 2018

## Odds and ends about truth

In my previous post, I proposed a somewhat limited theory of truth.  Here I’ll discuss some of the issues that might arise out of that theory.

### What if there are no relevant standards?

According to my theory, we assess the truth of a statement based on accepted standards for evaluating that truth.  So what will happen if there are no applicable standards?

The simple answer, is that we cannot assess the truth of that statement.

This is not really a new situation.  When Gödel proved his incompleteness theorem, he showed that there are mathematical statements (arithmetic statements) cannot be proved true or false.  Such statements are often said to be undecidable.  If you use my suggested theory of truth, then there will  be undecidable statements in ordinary life, and not just in mathematics.

The existence of undecidable statement has not been any kind of calamity in mathematics.  And it is unlikely to pose a serious problem in ordinary life.

### What about the law of the excluded middle?

According the the law of the excluded middle (or LEM), a statement is either true or false.  However, LEM is usually considered a law or reasoning, rather than part of a theory of truth.  Mathematicians still use LEM in their reasoning, following Gödel’s incompleteness theorem.  And it does appear to cause any problems.  I would expect the same to be true in ordinary life.  If you use my suggested theory of truth, you will not have to give up LEM as part of your reasoning strategy.

### Changing standards

What happens if we change standards?

March 5, 2018

## A modest theory of truth

I have previously discussed some of the problems that I have with the so-called correspondence theory of truth.  In this post, I shall suggest my own theory.

I am describing it as modest, because it does not attempt to settle all truth questions.  The use of “true” in ordinary language is a mess, and my theory will not attempt to address all such use.  Rather, it is intended only for technical uses, such as in mathematics and science.

In my last post, I made a distinction between ordinary mathematical statements such as $3+5=8$ and the axiom systems (such as the Peano axioms)  that we use to prove those ordinary statements.  There is widespread agreement on truth questions about those ordinary mathematical questions.  But there is less agreement about whether axioms are true.  Mathematics can be done, without settling questions on the truth of the axioms used.

Coming up with axiom systems is also part of mathematics.  But when a new axiom system is offered, the main concern is on whether that axiom system is useful.  Whether the axioms are true is often not asked, perhaps because there isn’t a good way to decide.  Axiom systems are usually adopted on a pragmatic basis.  That is, they are adopted for their usefulness.

Something similar happens in science.  The ideal gas laws of physics are a good example.  Those laws are true only for an imagined ideal gas.  They are false for any real gas.  But although technically false, they provide a pretty good approximation of the behavior of real gases.  And that makes them very useful.  So, with the gas laws, we see important scientific laws that are adopted on a pragmatic basis, even though they might be technically false.