Psychological theories are theories of the function of intentional states - Harman:
Beliefs and desires have distinctive functions, beliefs recording information about the world, desires specifying the goals of the system. Both sorts of states can be physically realized in various ways, perhaps even as states of intelligent machines.
These functions are about the relationship between systems and the world - Harman:
[psychological explanations] typically appeal to an actual or possible environmental situation of the creature whose activity is being explained.
Harman:
An animal has thoughts about food only if the perception of food under certain conditions can lead it to act appropriately toward the food, by eating it.
Agre:
As an agent gets along in the world, its actions are plainly about the world in some sense. In picking up a cup, I am not just extending my forearm and adjusting my fingers: those movements can be parsimoniously described only in relation to the cup and the ways that cups are used. A conversation about a malfunctioning refrigerator, likewise, really is about that refrigerator; it is not just a series of noisees or grammatical constructions. When someone is studying maps and contemplating which road to take, it is probably impossible to provide any coherent account of what that person is doing except in relation to those roads.
Harman:
Consider the hand-eye coordination involved in drawing a picture. This involves a complex interplay between perception and action. What is done next depends on the perception of what has been so far as well as the perception of hand and pencil. No explanation of what the agent is doing can avoid reference to the effects the agent's act has on the world and the agent's perception of those effects.
The need to relate inside and outside becomes clear when we think about the causal connections that we report when we explain how a system works.
Harman:
You do not understand what an automobile is and how it functions if you know only its internal operation independently of the fact that automobiles are vehicles that travel on roads to get people from one place to another, that the accelerator is pressed in order to make the car move, that the brake pedal is pressed in order to stop the car, that the gearshift is moved to a certain position in order to put the car into reverse so it goes backwards, and so forth. Similarly, you do not understand how people operate psychologically unless you see how their mental states are related to perception of the environment and to action that modifies the environment.
Harman:
Consider the following uninterpreted program: there are three possible input states, A, B, and C. A leads to output X and C leads to output Y; B has no effect. Do you understand what is going on? No. You need to know how the system is functioning. In fact, the system is a thermostatically controlled air-conditioner....
Harman:
Although we can test the functioning of automobiles and radio receivers in the laboratory even though they are not functioning to drive people from one place to another or to receive broadcasts from radio transmitters, our understanding of the functioning of the tested automobiles and receivers depends on our envisaging them in the relevant context, namely, the context in which they are used to transport people or to receive broadcasts. Similarly, we understand the functioning of a brain in a vat by envisaging it as part of a person in the relevant environment.
Putnam:
For the purpose of the following science-fiction examples, we shall suppose that somewhere in the galazy there is a planet we shall call Twin Earth. Twin Earth is very much like Earth; in fact, people on Twin Earth even speak English. In fact, apart from the differences we shall specify in our science-fiction examples, the reader may suppose that Twin Earth is exactly like Earth… One of the peculiarities of Twin Earth is that the liquid called 'water' is not H2O but a different liquid whose chemical formula is very long and complicated. I shall abbreviate this chemical formula simply as XYZ. I shall suppose that XYZ is indistinguishable from water and normal temperatures and pressures. In particular, it tastes like water and quenches thirst like water.
If a spaceship from Earth ever visits Twin Earth, then the supposition at first will be that 'water' has the same meaning on Earth and Twin Earth. This supposition will be corrected when it is discovered that 'water' on Twin Earth is XYZ, and the Earthian spaceship will report somewhat as follows: 'On Twin Earth the word "water" means XYZ.'
Or imagine that the words 'elm' and 'beech' are switched on Twin Earth:
Suppose you ar elike me and cannot tell an elm from a beech tree. We still say that the extneion of 'elm' in my idiolect is the same as the extension of 'elm' in anyone else's, viz., the set of all elm trees, and that the set of all beech trees is the extension of 'beech' in both of our idiolects… Suppose I have a Doppelganger on Twin Earth who is molecule for molecule 'identical' with me… It is absurd to think his psychological state is one bit different from mine: yet he 'means' beech when he says 'elm' and I 'mean' elm when I say elm. Cut the pie any way you like, 'meanings' just ain't in the head!
Harman, function and causality:
This [saying that narrow states - what you and Twin you have in common - and not wide states are what matter for psychological explanation] is like saying that Charles's pushing Bob out of the boat was not the cause of Bob's drowning, since Bob would have drowned no matter who had pushed him out of the boat. In an official investigation of the cause of Bob's death, it is more relevant that Charles pushed him out of the boat than simply that someone pushed him out of the boat or that his body was subject to a force that pushed him out of the boat.
Agre:
…any device that engages with any sort of interaction with its environment will exhibit some kind of indexicality. For example, ta theremometer's reading does not indicate abstractly "the temperature," since it is the temperature somewhere, nor does it indicate concretely "the temperature in room 11," since if we moved it to room 23 it would soon indicate the temperature in room 23 instead. Instead, we need to understand the thermometer as indicating "the temperature here" - regardless of whether the thermometer's designers thought in those terms.
Deictic intentionality is the predominant form of intentionality in the everyday activities of human beings. As an example of deictic intentionality, consider one's relationship to the utensils at a restaurant table. One's tabel generally comes equipped with a fork, a knife, a spoon, a glass of water, a napkin, and so forth, arranged in a customary pattern in reltaion to the table and chairs. In eating dinner, if all goes as usual, one adopts a deictic form of intentionality to these objects. That is, one treats them in just the same way in which one has treated all of the other forks, knives, spoons, glasses, napkins, tables, and chairs at all of the other restaurants at which one has eaten. Each of these entities plays its own role in a stable system of practices, and its objective identity does not normally arise as an issue. Just as the thermometer measures the temperature "here" and not "in room 11", so one eats with "this fork", or perhaps "the fork at my place at the table here" and not with "fork number 271403" in some cosmic registry of forks. Deictic intentionality is a prominent feature of everyday routine activity because everyday routine activity consists for the most part of embodied cultural practices that bring us into familiar relationships with familiar types of objects.
designer moves back and forth between two activities: synthesis of machinery and analysis of dynamics. The question of intentionality arises when it comes time to understand how one's artifact will interact with the people, places, and things that will populate its environment. The artifact will most likely interact with a given object in virtue of the object's role in the artifact's activities, not through the object's objective identity… an agent must … detect not simply the abstract "functionality" of objects but the role they play in the particular activities in which the agent is currently engaged.
This conception of the role of perception in activity makes strong claims on accounts of visual architecture. The principal purpose of vision, on this view, is not to deliver a world model; nor it is it to identify the objective identities of things; nor is it even to recognize and enumerate the categories into which visible objects might be classified. Instead, the principal purpose of vision is, starting from the agent's intentions and the changing visual field, to register the indexically and functionally significant aspects of the entities in the agent's environment. The work of registering these aspects frequently requires the agent to engage in complex interactions with the environment, and this work is indissociable from the rest of the agent's interactions. Vision is in this sense an active process, not the passive reconstruction of the world as it is projected onto the retina.
From Kinds of Minds
We human beings, thanks to the perspective we gain from our ability to reflect in our special ways, can discern failures of tracking that would be quite beyond the ken of other beings. Suppose Tom has been carrying a lucky penny around for years. Tom has no name for his penny, but we shall call it Amy. Tom took Amy to Spain with him, keeps Amy on his bedside table when he sleeps, and so forth. Then one day, on a trip to New York City, Tom impulsively throws Amy into a fountain, where she blends in with the crowd of other pennies, utterly indistinguishable, by Tom and by us, from all the others - at least, all the others that have the same date of issue as Amy stamped on them. Still, Tom can reflect on this development. He can recognize the truth of the proposition that one, and only one, of those pennies is the lucky penny that he had always carried with him. He can be bothered (or just amused) by the fact that he has irremediably lost track of something he has been tracking, by one method or another, for years. Suppose he picks up an Amy-candidate from the fountain. He can appreciate the fact that one, and exactly one, of the following two propositions is true:
- The penny now in my hand is the penny I brought with me to New York.
- The penny now in my hand is not the penny I brought with me to New York.
It doesn't take a rocket scientist to appreciate that one or the other of these has to be true, even if neither Tom nor anybody else in the history of the world, past and future, can determine which. The capacity we have to frame, and even under most circumstances test, hypotheses about identity is quite foreign to all other creatures. The practices and projects of many creatures requires them to track and reidentify individuals - their mothers, their mates, their prey, their superiors and subordinates in their band - but no evidence suggests that they must appreciate that this is what they are doing when they do it. Their intentionality never rises to the pitch of metaphysical particularity that ours can rise to.
How do we do it? It doesn't take a rocket scientist to think such thoughts, but it does take a Gregorian creature who has language among its mind tools. But in order to use language, we have to be specially equipped with the talents that permit us to extract these mind tools from the (social) environment in which they reside.