ON THE MODALS VI: Epistemic Modality II

Modalities are insanely and indescribably troublesome. From the ‘what do we mean’ to the ‘how do we know’ problems, philosophers still lose sleep on them and wake up thinking about them. However, things are getting better. We have seen Lewis solution to the former and we have seen Yablo with the latter. According to Yablo, we move from conceiving and imagining to knowing about the existence of modal objects. This week, we move on to Chalmers, who like Yablo also thinks we know about modal objects by our ability to imagine and conceive. In fairness, Chalmers can be seen as a rigorous development on Yablo. However, his rigorous attempt leaves much for amazement, and that is why he is worthy of consideration.

Let us begin with what Chalmers calls intensions. Intensions are a whole new way of explaining statements. Since we are now equipped with the possible-worlds device, statements are not just meaningful in our world any longer; we have to keep in mind that there are other worlds out there. You may say; “What the hell! What has other worlds got to do with the meaning of statements in our world?” In truth, you are right in thinking that. Sometimes, I stop in the middle of reading, writing and thinking about things of these sorts and I ask myself; “What is the point to all of these? What does it change that there are worlds out there or that we have to consider them when analyzing statements here in our world?” However, let me make a case for the philosophers, and hold unto the tiniest rope that it will be convincing.

Now, this is English not philosophy. Linguistic experts will tell you that to fully understand an expression, you must know its intension and extension. Intension is what you must know in order to determine the reference of an expression. For example, the intension of ‘car’ is ‘a vehicle for conveyance on road’. You have to know this fact about cars before you can point to what a car looks like. On the other hand, extension is the class of objects that an expression refers to. The extension of ‘car’ will include such things as motor car, bus, lorry, train-car, etc. Extensions do not change in any possible world because extensions depend on intensions for their meaning. However, intensions do change. I take you back to Barry Allen and the earth2 analysis to make this clear. Barry Allen was Barry Allen in both worlds, i.e. the expression ‘Barry Allen’ picks out the same individual in both earth1 and earth2. However, what we have to know to determine who Barry Allen is in both worlds are not the same. In earth1 he is the flash and in earth2, he is some lame journalist. Consequently, since we have to keep these two senses of meaning in mind when looking for the meaning of any expression, intensions become radically important. If someone who knows that Barry is the flash in earth1 but does not know that he is a journalist and not the flash in earth2, is asked who is Barry in earth2, he will point to the flash. But you now know such person would be wrong. Barry Allen does not pick out the individual that is the flash in earth2, rather it picks out a journalist. In earth2, the flash is Jay Garrick. So, in this way, it is remotely important to keep in our left hands what expressions in possible worlds. I can sense that the importance is still farfetched, but that is all I’ve got as far as convincing goes. In any case, philosophers think it best that we keep the intension of expressions in mind.

So, back to Chalmers. He says when the world in which you are evaluating an expression is our world then you are dealing with primary intension, but when the world is a possible world, then you are dealing with secondary intension. But before we go forward, let us look at how Chalmers break down the concept ‘conceive’. He highlighted six ways in which we often conceive by pairing them to make three ways. The first two are not really important for an introduction, so I skip them. The third however is important because he thinks that we only come to imagine something in a possible through the third way. The third way is ‘Primary conceivability vs Secondary conceivability’. In primary conceivability, what we do is we imagine the situation occurring in our world and in secondary conceivability, we imagine the situation occurring in a possible world. For instance, when we primarily conceived that the Germans could have won WWII, what we did was to conceive such situation and consider it occurring in our world. Likewise, when we secondarily conceive that the Germans could have won WWII, what we did was to conceive such situation and consider it occurring in a possible world. Chalmers disqualifies secondary conceivability because it depends on empirical evidence of what happens in our world. For instance, we say, “Although the Germans, did not win WWII, they would have been the world power had they won”. This is quite different from primary conceivability where we simply say, “The Germans could have been the world power, had they won WWII”. While the former holds fix the actual event, the latter suspends the actual event that the Germans did not win WWII. However, since modality requires no empirical investigation, we see why secondary conceivability does not yield access to modal facts.

Okay. So, primary conceivability it is. We have to imagine that the modal fact obtains in our world without holding fix what actually happens, and using only our ability to think. It is about go get a little bit complicated, so I implore you to pay close attention. Primary conceivability can either take on primary intension or secondary intension. When primary conceivability takes on primary intension, the imagined situation is epistemically possible, i.e. only possible logically. When primary conceivability takes on secondary intension, the imagined situation is metaphysically possible, i.e. occurs in a possible world. Since, our worry is how we come to know about what occurs in possible world and not what we can just conceive as possible, let us move on to discussing how secondary intension helps us know about modal objects.

I suppose I have mentioned it before that the standard account of what necessary and possibly mean is that something is possible if it is true in just one world and it is necessary if it is true in all possible worlds. Now, the secondary intension of any expression is the meaning of that expression when evaluated in a possible world. Since we already know that in our world, the Germans did not win WWII, even though the secondary intension of the expression “the Germans could have won WWII” is true in a certain possible world, it is merely metaphysically possible. It is only possible that “the Germans could have won WWII” because in at least one world – our world -, they did not win. In many possible worlds, they did win and that is why the modal expression “the Germans could have won WWII” is metaphysically possible. Likewise, since we already know that the modal expression “it is necessary that 2+2=4” is true in our world, and since its secondary intension is also true in a certain possible world, then it is metaphysically necessary that 2+2=4. It is necessary that “2+2=4” because in every possible world and in our world, the addition of two 2s equals 4. This is how the secondary intension enables us know about modal objects through our capacity to conceive.

The beauty of Chalmers theory is that it clearly puts the existence of these worlds and what goes on in them before our conceiving anything in them. If the Germans do not win WWII or 2+2≠4 in a certain possible world, there are no secondary intensions for our modal expression “the Germans could have won WWII” and “it is necessary that 2+2=4”. And if there are no secondary intensions, then we would not be able to conceive any such situation in the first place. His claim was that if there are no worlds in which the Germans did win WWII or where 2+2=4, then when we try to conceive situation in which the Germans won WWII or where 2+2≠4 occurring in a possible world, we would not be able to. We have come to the end of the guys in the conceivability camp. In the next post, we begin with those who think that we can know about modal objects by understanding the concepts used in the construction of our modal expressions. I know this post has been painted with heavy philosophical concepts and I apologize. Believe me, if I could have avoided them I would have. In that spirit, I would not be adding any further reading. See you next week.