What the [blank] do we know 2: Do you believe in logic?

You can lead a horse to water, but you can’t make him drink.

As I started to explore in a recent post, ““What the [blank] do we know?” our ability to reason our way to knowledge may be much more limited than we like to think. As much as I like Aristotelian logic and reason (and I like them a lot), I am aware that not all cultures think this way, and this kind of thinking is rarely, if ever, involved in either their decision-making or belief. The Old Testament, for example, tells the story of one of these cultures (although we try to evaluate it using our own adopted logical systems). The original Star Trek series tended to illustrate this point quite often, showing that Spock’s “pure” logic was not only “inhuman,” but often deficient to decision-making which combined logic and human emotion.

The questions then, for me, are: Does our current formal system of logic (based on the principles devised by Aristotle) represent the highest form of reason (thinking)? Relying on formal logic, what can we actually know?

One of the primary weaknesses with formal logic as a means to knowledge is that it usually presupposes that we actually know something to start with; even a priori knowledge is to some extent presuppositional. For example, the statement all men are not women seems patently obvious and logical; however, it presupposes as fact that there are 2 classes, men and women, which are mutually exclusive. Much of the time, the truth of a particular premise will not be so immediately obvious, and here is where a lot of flaky logic happens. It is possible to have a perfectly logical argument that results in a conclusion which is false, because it is based on a false premise. (Examples include every argument against the existence of God that I’ve ever seen.)

Logic, however, is still a wonderful tool in helping people get from point A to point E; it’s a great way of organizing what you know (or think you know) and believe, and how it shakes out. It is especially helpful in testing an idea or belief – often we find that when taken to its logical conclusion, some of our ideas are pure nonsense.

What logic is perhaps best used for is to challenge ideas and prove things false (or logically impossible). In fact, I would hazard a guess that it is much easier to prove something false than to prove something is true. For one thing, to prove something true, you have to account for all other possibilities. However, all you have to do to prove an argument false is to show that either a premise is not true, or that there’s a logical inconsistency somewhere.

But, (to show how tricky logic is) here’s the problem with my last statement: does proving that an argument is illogical mean that the conclusion is false? Unfortunately, no. What you can prove is that the argument is invalid, not the truth or falsity of most (especially a posteriori) statements (you could perhaps disprove “black is white” types of statements).

Again, logic is an extremely beneficial tool, but it is my opinion that logic cannot really prove or disprove truth. Now, I realize that theories of knowledge have been argued for centuries; it’s not my goal to be the next Kant, and I’m not going to debate the nature of a priori knowledge, etc.

My point, rather, is that logic has the same limitations that I discussed concerning scientific knowledge. Logic, even at its best, can only take us so far. An oft-used example is that of a chair. We can prove with impeccable logic that a certain chair is capable of supporting your weight. You carefully evaluate the argument and conclude that this conclusion is true. At this point, are you sitting in the chair? It still takes a decision for you to sit in that chair. Whether by logic, science, or supernatural revelation, you still have to make a decision based upon what you have chosen to believe as knowledge. Now, you are sitting in the chair, and have proved that the conclusion to our logical argument about the chair is true. Or have you?

Have you really proved that the chair can support your weight? Isn’t is possible that there is some other unknown, invisible force that is supporting you? You can’t even prove that you have considered all of the other possible options, because being finite we cannot possibly know all of the options. It would seem, then, that truth is impossible to prove either by logic or by experience, and it certainly can’t account for your belief.

You can lead someone to a conclusion (which may or may not be the truth) but you can’t make them believe.

Do you believe?