A little bit of philosophy: Lesson 2: Two truths

Now that we do to some extent understand what Hume said about cause we need to see what he has done with truth. The task, dear reader, is to try and predict what Hume's notions on truth might have for the possibilities of knowledge. That is, if we accept that our concept of truth has any bearing on our concept knowledge. Just keep such things in the back of your mind while you read on below.

To help us along on this particular journey to understanding what some theories in meaning are saying today: We are not studying the objects in the world anymore (no more metaphysics!) and we have done done done with meta-ethics too. Our proper and correct objects of investigation are the sorts of things that language yields: propositions being a particular favourite of mine and so appropriate for what we have set out to achieve in these few lessons. So, from now on I shall be giving you a proposition at the outset of various parts of any lesson. It is my wish that you do not forget to apply the lesson thereto and to nothing else. You may then have fun applying the lesson to other objects of the same category. If you are not certain whether your chosen object (proposition) is of the same category, I am always at the end of the comment-line.

It seems proper and correct that we pay credence to contingent truth as it has, after all, given us science and common sense. We start thus with this old dame:

Contingent truth

The proposition in question: All chairs are blue.

We have something someone asserts. This being "All chairs are blue." And then we have the conditions which would make such an assertion true. What could these be? It would simply have to be the case that all and every chair in existence must be blue in colour in order for the assertion above to obtain the truth value: true. Do you agree? So we have quite simply a condition which must obtain in the world in order for the assertion made about the world to be either true or false. The assertion would be false if it were found that even one chair is not blue or that the only objects which are blue are not chairs.

How would we find out if this were the case? In other words, how would we find out if the truth conditions for this proposition do, indeed, obtain? We would have to investigate the nature of reality. We would have to see what the world yields regarding the colour of all chairs. The investigation would be of the sensory kind. In science this is called empirical investigation and at the end of such an investigation things can turn out either in favour, or not, of the object under investigation. In other words, the world can turn out to either verify or falsify the proposition in question.

The point is that we need to go looking for the conditions which would settle the truth.

This is contingent truth. It is the sort of truth which is defeasible. Because new conditions can always turn up and overthrow what was previously thought to be true. It could be assumed, that every chair has been found and, as they are all blue, it could be thought that it is justified to take the proposition as true. But then one day, after having been buried deep underneath the soil of an old castle for instance, a red chair could turn up during an excavation. And suddenly the proposition is made false. And this is exactly how science does its work. Very tentatively. As it should.

Necessary truth

The proposition in question: All bachelors are unmarried men.

We have an assertion: "All bachelors are unmarried men" and then we have the conditions which would make such an assertion true. What could these truth conditions be, dear reader? Yes, naturally it would have to be the case that each and every bachelor, on finding such a thing, would have to have two qualities; being a man and being unmarried. You have learnt much I can see. These would have to be the conditions in the world for this statement to be true.

So, what then is different to contingent truth, you ask. It has to do with how we know whether every bachelor is indeed an unmarried man. The claim here is that we need not rise from our armchairs in order to establish if this really is the case. Such as with trying to find out if all chairs are blue, and then still being for ever uncertain whether this really is so. No. With objects such as "All bachelors are unmarried men" we simply know this to be true by definition. Because being a bachelor means that you are unmarried and that you are a man. There is no other way of being a bachelor, unlike the possibility of being a chair and not being blue. We say, that bachelors by necessity have to be unmarried and a man, but that chairs do not, necessarily, have to be blue. This is a matter of contingency.

Regarding the troublesome question of how I know whether the conditions obtain so needed to make the bachelor proposition true. I know this by definition. I know that if I were ever to find an object called a bachelor this object will be unmarried and a man. If this were not the case it could not be called a bachelor. There is, therefore, a necessary relationship between the concepts "bachelor", "unmarried" and "man".

And such truths are what Hume called logical truths. Definitions are logical truths, analytical truths are logical truths and correct mathematical equations are logical truths. They are truths which are not defeasible in any way. Because they have to do with logical equivalence of some type or another. And there are different types. But this is for another day.

Do you think you have an example of a defeasible necessary truth? Let's hear about it then.

Next lesson: What does this distinction mean for knowledge?