Propositional Attitudes

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Transcript Propositional Attitudes

Summer 2011
Monday, 07/25
Recap on Dreyfus
• Presents a phenomenological argument against the idea that
intelligence consists in manipulating symbols according to
formal/syntactic rules (the PSS hypothesis).
• Tries to describe the
experience of becoming an
expert in “slow motion”:
Novice  Advanced Beginner
 Competent  Proficient 
• Claims that paying close
attention to this progression
reveals that being an expert is
not a matter of following
“internalized” rules at all.
• It is, in fact the other way
around: becoming an expert is
getting away from rule
following altogether.
Knowing How vs. Knowing That
• Knowing-that = Propositional Knowledge.
Knowing some set of facts, e.g. the fact that
Paris is in France or the fact that one should
do such-and-such in a certain situation.
• Knowledge-how = “Procedural knowledge”,
having an ability to do something, e.g. to drive
a car, ride a bike, ski, weld metal, etc.
Kinds of Knowledge
• Knowledge-that is fundamental. Many types
of knowledge, e.g. knowledgewhere/when/who/what, may be understood
in terms of knowledge-that.
• But some kinds of knowledge, e.g. knowledge
by acquaintance (many languages have special
words for this!), may not be understood in this
• It’s an open, controversial question in
philosophy how knowledge-how relates to
Propositional Attitudes
I think that Paris is pretty.
You hope that Paris is pretty.
Jon believes that Paris is pretty.
Paul says that Paris is pretty.
Laura and Jim wish that Paris is pretty.
These people expect that Paris is pretty.
The bold terms seem to refer to types of mental states.
The underlined clauses seem to refer to propositions.
A PROPOSITIONAL ATTITUDE is a mental state that relates
someone (e.g. a person) to a proposition. Propositions
are the intentional objects of propositional attitudes.
• Mind/Language Independent. Two people can be
related to the same proposition, even if they
don’t share a language.
• Are Abstract. You can’t encounter or them or
perceive them through the senses.
• Can be true/false. The conditions in which a
proposition would be true/false are essential to
the proposition.
• Often used in common sense, psychological
explanation, e.g. I believe the same thing that she
does, she said what I wanted to say, we both
expect the same thing to happen.
• We can think of propositional attitudes
asmental states that are about propositions,
or that involve “grasping” them.
• Believing, hoping, desiring, expecting (and so
on), are all different ways of entertaining (or
grasping) propositions.
Propositional Attitudes
Tricky questions arise, among them:
1. What exactly are the mental states that relate us to
propositions? What is a thought, a belief, a hope, a
2. How does a mental state, of whatever stripe,
manages to relate a person to a proposition? What is
it to “grasp” a proposition?
3. What explains the difference between the various
ways of entertaining propositions (e.g. believing,
hoping, desiring)?
4. Why is it that entertaining some propositions, in
certain ways, leads us to systematically (rationally,
intelligibly) entertain certain others, in certain
appropriate ways? What’s the scientific explanation
of this fact?
Representational Theory of Mind
A framework for understanding the
propositional attitudes, defined by these
1. Propositional attitudes pick out
computational relations to internal
2. Mental processes are causal processes that
involve transitions between internal
“To a first approximation, to
think “it’s going to rain; so I’ll
go indoors” is to have a
tokening of a mental
representation that means
I’ll go indoors caused, in a
certain way, by a tokening of
a mental representation that
means, it’s going to rain.”
• “Folk Psychology”, or our
common sense theory of the
mind is largely correct.
• Thoughts, beliefs, desires
(and so on) are real innerstates.
• These states are built out of
symbols (e.g. brain states
and processes) that causally
interact with other mental
• Science will validate our
common sense
understanding of ourselves
by identifying inner states
whose meanings and
structures closely match the
contents and structures of
daily ascriptions of
propositional attitudes (with
some room for
• There are no inner states that
closely match our talk of
propositional attitudes, i.e.
there are no beliefs, hopes,
desires, and so on.
• As science progresses, we will
drop talk of such entities and
adopt an entirely new,
scientific way of talking about
our psychology.
“We need an entirely new
kinematics and dynamics with
which to comprehend human
cognitive activity. One drawn,
perhaps, from computational
neuroscience and
connectionist AI. Folk
psychology could then be put
aside in favor of this
descriptively more accurate
and explanatorily more
powerful portrayal of the
reality within.”
Tries to steer a middle
course between Fodor and
Like Churchland, anticipates
no close match between the
folk and scientific
understanding of ourselves.
But holds that the goodness
of the common sense
understanding is established
independently of particular
facts about implementation.
psychology is a useful
tool for making sense of
the mental lives and daily
behavior of rational
It is a special case of the
“design stance” that we
take towards artifacts, a
way of understanding
things in reference to
what they’re supposed to
Our common sense
psychology is “a
rationalistic (i.e.
calculus of interpretation
and prediction—an
idealizing, abstract,
interpretation method
that has evolved because
it works and that works
because we have
Dennett’s view is complex. He does
not claim that there are no beliefs.
Instead, folk-psychology works
because there exist real, objective
patterns in human and animal
behavior that are fully observer
Mental states are real in the same
sense as “abstracta” such as
centers of gravity or the equator
are real.
We’ll talk a lot more about each of
these three views in the next three