The solution
Actually, the solution is pretty simple, once you see it.
If we now suppose our Frenchman sends another message--say, "Les sanglots longs des violons de l'automne," and so on, then this will be translated into--note--a different pattern of clicks, which will then be translated into a different pattern of radio waves, which will then get translated by the receiver into a different set of ASCII codes, which the printer will print out into something like, "Whose woods these are I think I know." Once again the message sent is entirely different from the message received; but if the reader now reads the two messages received, he will conclude what we did when we looked at the many forms of consciousness: "Since my receiver is the same both times, then different messages must have been sent."
Similarly, when I look beside my dog at the grass, and my consciousness responds with a different type of visual consciousness, I know that what it is about the dog that affects my eyes (that particular existence) has to be different from what it is about the grass that affects my eyes.
This is even more evident than in the case of the messages above because I am looking at both the dog and the grass with the same eyes at the same time; they are both within my field of vision. But if different effects have different causes (and they do; this was Theorem IV of Section 2, remember), then my eyes and my mind can't account for the difference, and so the difference has to be due to the fact that the grass is different in the act by which it affects my eyes from the act by which the dog affects my eyes (see how handy the term "act" is?).
If we take another step, we can see our way to the key to the solution. If we assume that our Frenchman now sends, "Allons, enfants" over again, then, supposing once again the same set of apparatuses, the message received will again be "Fourscore and seven." And this, of course, is what we were driving at when we said that repetitions of the same form of consciousness imply the same existence.
But this is a little broader than we stated originally. If I look at the grass and then I look up at the trees, and then look at emeralds, and if I look at traffic lights, I get the same visual reaction every time--or at least very similar ones, and ones vastly different from the visual reactions of looking at my dog or the sand or camel's hair coats, or varnished pine boards--which are also similar among themselves as visual reactions.
Then what this must mean is that grass, trees, my monitor, emeralds, and traffic lights act somehow similarly to each other and differently from the dog; while the dog, the sand, the coat, and the wood act similarly to themselves and differently from the grass.
We have begun to classify, in other words. Differences in the form of consciousness imply differences in the existences; similarities in the forms of consciousness imply analogies among the existences: the existences have to be somehow similar if the forms of consciousness are similar.
And this allows us to interpret what is meant by "intentional identity": If a person keeps getting the message, "Fourscore and seven" among a whole series of other messages, then he knows that, whatever the message was that was sent, the same one is being sent whenever "Fourscore" is received; and so he could now take "Fourscore" as "standing for" whatever it is that caused it, and "intending" that, or "referring to it," especially since it is a message received and not one he typed on his own keyboard.
So even though there is a difference between the message received and the message sent, once one recognizes that (a) the message received is received (i.e. that you are perceiving and so reacting-to), and (b) that this particular message always is the way a given (unknown-in-itself) message sent was received, (i.e. this type of perception reacts to some definite act) then the message received can be understood as "pointing to" the unknown message sent as distinctive--without ever knowing what the message sent actually was.
And this solves the Kantian problem. We don't know what the existence "out there" is in itself; what we know is what other existences it is related to, and what the relationship is, based on our conscious forms as effects of existences. We know what it is like, what it is beside, what it is the cause of, what it is the effect of, what it is unlike, etc., etc. In all cases, what is known is the existence as related, not the "thing in itself."
But this is real knowledge--and it is objective. I may not know what "green" is as such; (i.e. I may not be able to reproduce the act green in my consciousness, as Aristotle thought I could); but I do know that whatever it is, it's an act of grass, trees, and emeralds: I can recognize the act when I see it because I can (a) know that I am reacting to it, and (b) distinguish it from acts that cause different effects on me and (c) liken it to acts that cause the same effect.
Note that "intentional identity" is not "identity of informational content," as if the message sent was sent from a different country, but the actual messages sent and received were the same. After all, the contents of the message is the informational content. No, the messages are totally different from each other. There is no question of "matching" the perception with its cause; intentional identity simply means that a given perception points to a given (totally different from it) cause.
And since we can never get "outside" our minds, we can never know what that cause is, in the sense in which we know what our conscious act is; we can only know that, whatever it is, it is the same as whatever affects us in the same way, and different from what affects us differently, and in general that relations between the effects will be the same relations as the relations between these unknown causes.
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