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Against Intentionality

Frege's mistake lay in assuming an appealing theory about why people say what they do. He thought people believe sentences true because they believe what those sentences say.  If so, then what someone thinks must exactly reflect what he would candidly assert.  The theory appeals because it assumes a even simpler picture of thinking: it is the picture of thinking as talking to yourself, sotto voce.

Frege didn't invent this way of thinking about thinking, but he was the first  to see how much must follow about thought and language if it is true.  If we take it as analytic that beliefs have the functional role Frege assumes for them, we can define Frege Beliefs:

x believes_F p =_df  x would believe ^┌p^┐ was true iff x understood ^┌p^┐

When contemporary philosophers talk about the "narrow", "notional", "opaque" or "internalist" sense of 'believes' they are talking about belief_F.

The theory extends to the other attitudes. Thus we have Frege Desires:

x wants_F that p = _df x would want ^┌p^┐ to be true iff x understood ^┌p^┐ .

And supposing that what you understand are meanings, we can define Frege Meanings :

x understands the meaning_F of ^┌p^┐ =_df x would believe ^┌p^┐ was true iff x believed_F p.

Frege called the meanings_F of sentences "thoughts" and the meaningsF of words "senses".  As Michael Dummett tells us:  "The sense is that part of the meaning of an expression which is relevant to the determination of the truth‑value of a sentence in which the expression occurs".  We can specify the Frege Meaning or sense of a term thus:

x understands the meaning_F of ^┌a^┐ =_df  x would believe ^┌..a...^┐ was true iff x believed_F ...a...

After Frege, when philosophers spoke about "meanings" (and after Frege, they spoke of little else) they were always talking about meanings_F.

These equivalences don't count as ampliative definitions since meaning_F and belief_F are defined reciprocally.  A proper analysis would have to define either 'belief_F' or 'meaning_F' in terms that did not assume the other.  However, despite generations of effort, finding a non-circular analysis has proved problematic.  It is one of those philosophical problems that has grown capital letters: it is " The Problem of Intentionality".

A word about the word "Intentionality".  As all the texts will tell you, the term was introduced as a philosophical technical term by Brentano, who intended it to pick out what was distinctive about the mental. So what is "intentionality"? Like so many philosophical technical terms, it can only be explained with a waving of hands.

" Intentionality has to do with the directedness or aboutness of mental states — the fact that, for example, one's thinking is of or about something."

"Intentionality is the power of minds to be about, to represent, or to stand for, things, properties and states of affairs."

This makes "intentionality" sound like some sort of spooky power.  But on reflection there seems nothing spooky, or particularly mentalistic, about "aboutness".  You can throw your arm about your friend.  The moon circles about the earth.  The price of gas is about four bucks a gallon. Nothing mental here.  These kinds of "aboutness" are just garden variety relations that one item can have to another.

What is distinctive about the "aboutness" that is supposed to characterize mental states is precisely that it is not a relation between a mind and what it thinks about.  Relations require relata.  You can't put your arm about something unless it exists.  On the other hand it seems you can think "about something" even if it doesn't exist.  Don't children have beliefs about Santa?  They must.  After all, they say things like “Santa is coming tonight."  Then, too, ordinary "aboutness" relations are relations between things, no matter what you call them.  A moon couldn't orbit about Hesperus without orbiting about Phosphorus; Hesperus is Phosphorus.  But apparently you can think about Hesperus without thinking about Phosphorus; after all, someone could think 'Hesperus has a moon' was true but deny 'Phosphorus has a moon'.

So what's special about the aboutness of intentional states is that these states manage to be "about " things without actually being... well, about things.  Which, come to think of it, is kind of spooky.

Frege's Mistake

In a recent post I told the story of Ralph, 'Hesperus' and 'Phosphorus'.  We saw there why Ralph might assert

('h≠p')    'Hesperus ≠ Phosphorus'

and how astronomical observation might lead him to change his mind. Remarkably, at no point in telling that story did we find any reason to deny that

(Bh=p)    Ralph believes Hesperus = Phosphorus.

It was not that we refused to take Ralph at his word.  Ex hypothesi, Ralph is a competent speaker of English and we took him to be sincere when he asserted ('h≠p').  We had to conclude that:

(Bh≠p)    Ralph believes Hesperus ≠ Phosphorus.

The principle at work here is an important one.  I call it (following Kripke) "The Disquotation Principle":

Lo, Hesperus. Lo, Phosphorus.

Here is Ralph. Ralph is a competent speaker of English. In particular, Ralph understands the words 'Hesperus' and 'Phosphorus' and knows what they refer to. When you are walking on the moors with him and he says "That's Hesperus!' or "There is Phosphorus!', you can be sure it will be Venus he's pointing at. Nevertheless, Ralph denies:

(HP)    'Hesperus = Phosphorus'

Though, of course, he would never deny:

(HH)    'Hesperus = Hesperus'

If we take Ralph at his word in denying (HP) we must conclude that Ralph believes that Hesperus ≠ Phosphorus in other words, that he believes Venus ≠  Venus. And given his endorsement of (HH) we may conclude that he also believes that Venus = Venus.

Ralph might puzzle us if we thought that psychological explanation must make sense of people in terms of what propositions they believe. But, as we have already observed, this is a mistake.

Psychology in Two Dimensions

It has been clear since the discovery of Twin Earth that there must be two different determinants of the propositional attitudes. Our Twin Earth doppelgangers are atom for atom identical with us.  Any psychological theory— any theory about how sensory inputs get translated into behavioral upshots— true of us must be true of them.  And yet, because of our different environments, we and our twins have different propositional attitudes.  Apparently, these differences in what we think and think about, must be irrelevant to psychology.  How can we reconcile this with our folk psychological conviction that people do what they do because of what they think?

Suppose that we one day have to hand The One True Psychological Theory of Human Beings.  Like any theory it will have a proprietary vocabulary– a way of carving up the world into psychological natural kinds– and a finite set of laws.  While we do not know what those laws are, we can be sure they will entail any number of nomolological regularities of the form:

(L)       ("x)( Ψ¹x at t₁ É Ψ²x at t₂)

where the ‘Ψ’s name individuals’ total psychological states; everything that can be said about them in the terms of the Theory.

The lesson of Twin Earth is that individuals might share the same total state but believe different things.  What propositional attitudes one has depends upon extra-psychological facts about the world in which one realizes that state and about one’s location in time and space in that world.   I’m going to call these locations in possible worlds situations (with applogies to Perry and Barwise).

I write:

in σ in Ψ: x believes p

to say that, in a certain situation σ, someone in state Ψ would believe p (among, presumably, many other things).  In Putnam’s story the situations and states are such that:

In σ_e in Ψ: x believes rain is H2O.

In σ_t in Ψ: x believes rain is XYZ.

It might be tempting to gloss all this by treating psychological states as functions from situations onto attitudes, but this would be a mistake.  Functions are identical if they yield the same values for arguments but psychological states can be different in psychologically potent respects even though the differences don't show up as differences in what subjects think or think about. (see. "Now,Me")

If we were perfect epistemic engines, our psychological states would be realized by true beliefs in every situation in which we found ourselves.  Alas we know that isn’t so and the situation dependence of the attitudes reveals another source of error.  A psychological state realized by true beliefs in one situation might be realized by false beliefs in another. 

Here is Oedipus insisting, “My Mom is not my wife”.  The proposition he believes is false; indeed, necessarily false by some ways of reckoning.  But Oedipus is not irrational or unfathomable, only badly situated.  Surely things could be arranged, behind the scenes, over on Twin Earth, so that Twin Oedipus is married to a woman who is not his mother, without it making any difference to what is in Twin Oedipus’s head. 

Twin Earth, so constructed, is what Dan Dennett, would call one of Oedipus’s “notional worlds”.  That is, worlds or , better,  (since Twin Earth is in our possible world) , situations in which Oedipus’s psychological state would be realized by true beliefs.

Dennett noticed that, for the purposes of explaining behavior, what matters is not what propositions subjects actually believe, but what they would believe in their notional situations.   This makes sense from an evolutionary point of view.  Presumably, true belief has survival value.   But evolution can operate only on what is inside our heads and what we believe and whether it is true is largely determined by what’s outside.  However clever we may be, we may still, like Oedipus, end up badly situated.  On the other hand, it would be a poor psychological design that allowed us to get into psychological states that could not be realized by true beliefs in any situation. Thus we might expect that the psychological states of well adapted organisms would be realizable by true beliefs in at least some situations.  Moreover we should expect those organisms to behave and think in ways that were appropriate to those notional situations.  As I will put it, your notional situations are the sorts of situations you think are in. 

As folk psychologists we are adept at understanding one another in this way.  If we are told that someone believes the proposition that Jocasta ≠ Jocasta, we have no way of telling what he might do.  On the other hand if we know that someone thinks they are in a situation of the sort Twin Oedipus is actually in, we understand his psychological state, know how he might have acquired it and how he is likely to respond to what happens next.

What happens next in the Oedipus story is that a group of messengers arrive telling tales.  Listening to them, Oedipus and Twin Oedipus will change their common psychological state until each them comes to think he is in a situation in which it is immensely probable that his mother is his wife.  At that point, in a transition described by laws like (L), the penny drops.  Oedipus and Twin Oedipus move into a new psychological state which is realizable by true beliefs only at situations in which they have committed incest.  Oedipus’s actual situation has become his, and Twin Oedipus’s notional one.  And both behave appropriately to that situation; they go ape, as anyone would if he thought he was in a situation in which he had married their mother. 

In the course of the story, Oedipus and Twin Oedipus acquire new beliefs given what they see and hear.  Assessed in terms of propositional content, they learn very different things.  The messengers hither are telling the awful truth about Jocasta; over yon, they are telling ugly lies about Jocasta’s twin.  Still, the Oedipi’s sensory inputs will be psychologically indistinguishable and will have identical effects on their psychological states and notional situations.   For the purposes of explaining and predicting behavior, the most productive way to characterize empirical uptake is not in terms of what propositions it is evidence for or what  propositions it might lead a subject to believe, but rather in terms of its effects on the subject’s notional situations.   By this accounting we can say that in our story both Oedipi make the same inferences based upon the same information.  Of course, they end up with different beliefs.  In Twin Oedipus’s case: necessarily false beliefs;  but that is beside the psychological point. 

Likewise it is natural to want to describe Oedipus' change of mind through the course of this story as an increase in knowledge.  By the end of the story he knows something about Jocasta he did not know before.  But, as we shall see in later posts, this sort of epistemic gain cannot be understood in terms of learning new propositions, but by coming to believe propositions already believed, by way of different, more informed, psychological states.  Knowledge is a matter of information, not justification.

Of course, mistakes about identity have had a special philosophical luminance ever since Frege wrote about The Morning and The Evening Star.  In the next post on this theme, we will put two dimensional psychology to work at sorting out sense and reference.