Joe Lau's wiki: Main/Semantics Of Mental Representations

Readings

• [Required] Block, Ned (1998). Semantics, conceptual role. In E. Craig (Ed.), Routledge Encyclopedia of Philosophy. London: Routledge. routledge:W037
• [Required] Gallistel, C. R. (2001). Mental representations, psychology of. In Encylopedia of the Behavioral and Social Sciences. New York: Elsevier. Pre-print version available online at http://ruccs.rutgers.edu/faculty/GnG/Mental_Reps.pdf
• [Required] Section 4.2 of In Tye, Michael (1995). Ten Problems of Consciousness : A Representational Theory of the Phenomenal Mind Cambridge: MIT Press. [accessible from http://www.netlibrary.com]
• Pitt, David. Mental Representation. The Stanford Encyclopedia of Philosophy stanford:mental-representation
• Bach, Kent (1998). Content: wide and narrow. In E. Craig (Ed.), Routledge Encyclopedia of Philosophy. London: Routledge. routledge:W040SECT2
• Lau, Joe, Externalism About Mental Content. The Stanford Encyclopedia of Philosophy stanford:content-externalism

Intentionality and content

• Intentionality is a central feature of the mind. We take perceptual states, memory, beliefs, concepts, images, etc. as mental states with content.
• Representation is a core part of theories in cognitive science - X represents Y; X means Y; X is a representation of Y.

Three questions:

Eiffel Tower

1. Which object is the representation? (Vehicle)
2. What does it represent? (Content)
3. Why is it that the object has the representational content it does? (Link)

A conventional account of meaning for natural language does not work for mental representations.

• Example : David Lewis's account. stanford:idiolects/appendix.html

Causal covariation account of content

Gallistel

@A mental representation is a system of symbols isomorphic to some aspect of the environment, used to make behavior-generating decisions that anticipate events and relations in that environment.@

• This theory seems applicable to some representations, e.g. representations in the early visual system.
• But how about the content of our experiences in some visual illusions? In such cases, there are aspects about the contents of the experiences which are not isomorphic to the structures in the world - misrepresentation.

Michael Tye

@S represents that P = If optimal conditions obtain, S is tokened in x if and only if P and because P.@

• This proposal allows for misrepresentation.
• Problem #1 - the problem of causal intermediaries : Suppose P causes Q, and Q causes S. Does S represents P or Q?

• Problem #2 - representational objects that do not exist : What about beliefs concerning Santa Claus, desires and thoughts about the future?

Tye says explicitly that his proposal is only intended for perceptual representations.

@Obviously, this approach needs further amplification; but I have said enough to comment on the question of whether it can be used to understand mental representation generally. Clearly, there are difficulties. In particular, the account is not straightforwardly applicable to beliefs across the board. Take, for example, the belief that the Devil is an angel who fell from grace. What are the relevant optimal conditions here? And what about mathematical beliefs, the belief that 2 + 2 = 4, say?@

Conceptual role semantics

Ned Block

@According to conceptual role semantics (CRS), the meaning of a representation is the role of that representation in the cognitive life of the agent, for example, in perception, thought and decision-making. It is an extension of the well-known 'use' theory of meaning, according to which the meaning of a word is its use in communication and, more generally, in social interaction. CRS supplements external use by including the role of a symbol inside a computer or a brain.@

Wittgenstein (section 43, Philosophical Investigations)

@For a large class of cases -- though not for all -- in which we employ the word "meaning" it can be defined thus: the meaning of a word is its use in the language.@

What is inferential role?

Global inferential role

Peter jumped into a volcano.
⇒ Peter is dead.
⇒ Peter was crazy.

Analytic inferential role

Peter is a bachelor.
⇒Peter is male.
⇒Peter is single.
⇒Peter is not a rock.

Logical inferential role

• What does "#" mean?
  • P#Q ⇒ P
  • P#Q ⇒ Q
  • P, Q ⇒ P#Q.
  • it is not that case that (P#Q) ⇒ either it is not the case that P, or it is not the case that Q.

2-factor versions of CRS

Conceptual role includes an internal and an external component.

• Internal role - role of the representation that is purely within the brain of the agent.
• External role - role of the representation including its connection to the environment.
• Causal psychological explanations require the internal conceptual role component .
  • "I am here." vs. "I am in HKU."
• Explanations of truth-conditions require the external component.
  • "water is wet." (on Earth) vs. "water is wet." (on Twin-earth)

@ In the famous "Twin Earth" thought experiment in Putnam (1975), we are asked to imagine that in 1750, there was a remote planet, Twin Earth, which was exactly like Earth except that instead of water (H2O), it had a different substance twin-water, say a different chemical compound XYZ. The macro properties of XYZ are supposed to be just like water : it looks and tastes like water, and it could be found in the rivers and oceans on Twin Earth, and so on. However, back in 1750 nobody on Earth or Twin Earth could distinguish between water and XYZ. Still, according to Putnam, an individual on Earth in 1750 who used the word "water" would have been referring to H2O and not XYZ. Of course, this person did not know that water is H2O. But according to the externalist, this should not have prevented him from referring to H2O when he used the term "water". If he had pointed to a sample of XYZ and said “That's water,” he would have said something false. Similarly, when an individual on Twin Earth in 1750 used the word "water", he would have been referring to XYZ and not H2O. stanford:externalism @

Class discussion

• Comment on this quotation.

@"What we see at any given moment is in general a fully elaborated representation of a visual scene." From Churchland, Ramachandran, and Sejnowski (1994). A critique of pure vision. In Koch and Davis (Eds.) Large-Scale Neuronal Theories of the Brain Cambridge: MIT Press.@

• If someone subscribes to the two-factor version of conceptual role semantics, what might such a person say about the conclusion of Searle's Chinese Room Argument?
• Some people argue that the twin-earth thought experiment shows that beliefs "are not in the head". Is this right? See stanford:externalism

Category.Mind