Notes for BBK II.
This section of the paper opens with an important (initial) distinction between two ways in which
Sellars sees the intellect as isomorphic to the world:
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An isomorphism in the real order (here we have what Sellars calls picturing).
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An isomorphism in the logical order (here we have what Sellars calls signifying).
The key point about this distinction is that items involved in the picturing relation are to be
conceived as parts/features of the real order—picturing, then is a matter of purely descriptive facts about
relations between the intellect (or overt language) and the world. But signifying involves items in the
logical order—signifying is a matter of relations between the normative roles which the terms involved
(mental words & words in some other language) play in their respective languages.
So when we say “the intellect pictures the world,” we are claiming a certain kind of matter-of-fact
relation holds between the intellect, as described by natural science, and the things the intellect represents.
But when we say “the intellect signifies the world,” we are claiming a normative parallel between the roles
of certain states of the intellect and the roles of words and other linguistic items in some language: the key
theme here is translation. This combines Sellars’ analogy view of the concepts we use to characterize
thoughts (states of the intellect) with the normative element of intentions & their relation to a community
whose commitments and shared intentions give those intentions content.
For the intellect to signify the world, it must picture the world—but not vice versa: no norms, no
relation between individual and community intentions, no intentions at all, in fact, are required for picturing
to happen. Sellars draws on the parallel he asserts between thought and language, and focuses, in the
subsequent exploration, on overt language to illuminate what he wants to say about thought—further, he
appeals to an imaginary robot to tell the story he wants to tell about language.
The robot wanders around, inscribing “sentences” (sequences of marks) on a tape. The
“sentences” are produced in response to sensory inputs, including inputs from the robot’s own reading of its
tape, and also by “reasoning” processes (deductive and inductive) within the robot, which lead it to inscribe
other “sentences.” The “sentences” also include marks whose inscription precedes various kinds of actions
(something like “I shall now move to the north,” which is—when sincerely uttered—regularly
accompanied by northerly movements). Sellars notes two isomorphisms at work in our account of such a
robot. First, we can find regular correspondences between marks of various types inscribed on the tape,
and facts about the robot’s environment and about the robot itself. This is the picturing isomorphism, and
(as we noted above) it holds between natural, purely descriptive features of the tape and features of the
environment (note further that this isomorphism cannot be divorced from the robot systems that ensure the
correspondence holds). But, when we find that the tape symbol ‘::’ bears a regular relation to occurrences
of lightning, we may also be tempted to describe this symbol as corresponding to our word ‘lightning’.
This isomorphism is very closely related to translation, and holds between items conceived as playing
certain roles in the systems of rules governing use of ‘::’ on the robot’s tape and ‘lightning’ in English.
Sellar’s views on signification emerge largely on pages 54-7. The difference between ‘Mensch’
signifies man and ‘Mensch’ has the same use as ‘man’ is just that in the first, we assume that ‘man’ is part
of our vocabulary.
The Thomist, according to Sellars, confuses this logical relation (logical in the sense that the use
in question here is use as specified by a system of inference rules) with the picturing relation, and so reads
‘Mensch’ signifies man.
as asserting a relation between something in the logical order (a word governed by norms of use) and
something in the real order. If this (for Sellars, confused) relation is the key to the isomorphism of the
intellect and the real, and if we drop the word ‘Mensch’ here (tokens of which are clearly not isomorphic in
any direct or simple way to men or manhood), in favour of the thought or idea (the intellectual word)
‘Mensch’, then the temptation to regard the thought as somehow like men in general (or as being imbued
with a character like the character that makes men all men) becomes very strong. And since the thought of
man is clearly not a man, the idea that it partakes of manhood (the universal nature) in a different way, i.e.
immaterially, arises as a way of grounding this claim of an isomorphism.
Sellars’ way out of this argument for the immateriality of the intellect is to argue that, when we
keep the two isomorphisms distinct, while recognizing that the picturing isomorphism is a kind of prerequisite for the isomorphism of signification, we are no longer tempted to believe in a “mixed”
isomorphism, between thought as logical (i.e. governed by norms) on one hand and things in the world on
the other. And the isomorphisms that remain, linking thoughts as logical items to the corresponding words
in overt language, and thoughts as natural items to various circumstances and states of affairs in the world,
make sense as isomorphisms without any such dual realizations (immaterial and material) of one and the
same “feature” of things.
Finally, Sellars reiterates his rejection of Descartes’ argument for the immateriality of the mind.
The key point here is that Descartes assumes, when we have non-inferential knowledge of what we are
thinking, that we must grasp those thoughts as they are in themselves (in propria persona). Given this
assumption, Descartes points out that I can know I’m thinking of a horse even though I don’t know that I
am in some particular sort of state of my CNS. So the fact that I’m thinking of a horse can’t consist in the
fact that I’m in some particular state of my CNS. After all, if in knowing that I’m thinking of a horse I
know that thought in propria persona, I must know it for what it really is—and since I can know I’m
thinking of a horse without knowing I’m in that CNS state, it follows that that CNS state can’t be what the
thought really is.
Sellars’ response to this argument for dualism is just to say that the epistemic assumption here is
wrong. We can have non-inferential knowledge of our thoughts (and about our surroundings, too) without
grasping them as they are in themselves (i.e. in the terms we would use to describe them within the
scientific image). All we need to have such non-inferential knowledge is to be able to put a practice in
place, of making such reports authoritatively (norms come with authority here). All we need for this to
work is to find we can report reliably on the fact that states conceived merely as bearing a certain
isomorphism to certain overt utterances are occurring in us—and this can be determined by seeing whether
the resulting stories about what’s going on “in our minds” make good sense of what we do and say.
So Sellars closes this essay with a form of physicalism: “the intellect…as belonging to the real
order…is the central nervous system…What we know directly as thoughts in terms of analogical concepts
may in propria persona be neurophysiological states.”