There are two different kinds of arguments for a Rationalist
approach to the study of mind. The first, so far as I can tell, is virtually
tautological. The second is quite substantive.
What are they? I’ll try to lay them out in a couple of posts. This one
here discusses the “tautology.”
The tautological version is well laid out in the Royaumont
conference papers (here)
and how they relate to the innateness “controversy.” I put the latter in quote marks because most
of the participants (including and especially Fodor and Chomsky, the so-called
hard core nativists) considered the idea that the mind has innate structure nothing
a simple tautology. Indeed, this is how Fodor and Chomsky repeatedly refer to
the “innateness hypothesis” (see e.g. 263, 268). It’s tautological that the
mind (and brain) has structure and biases as without such there can be no
induction whatsoever and it is taken for granted that biological systems are constantly
inducing (viz. engaging in non-demonstrative inference). This said, it is interesting to re-read the
discussions for despite this general agreement, there is lots of intellectual
toing and froing. Why? Because as Chomsky puts it (see Fodor’s version p. 268):
What is important is not just to
see that something is a “tautology,” but also to see its import. (262)
What’s the import, as Fodor and Chomsky understood
things? That there is no “learning”
without a set of given projectable
predicates that undergird it. Or, more accurately, as Fodor puts it, “ the very
idea of concept learning is confused”
(143). And the confusion? Two related,
but importantly different, concepts have been run together; concept acquisition
(CA) and belief fixation (BF). Regarding the former, we have no theory of how
concepts are acquired. What we have are theories of BF, which are, at the most
general level, inductive logics of various kinds, which, by their nature, presuppose a given set of projectable predicates and so cannot themselves serve as theories of CA. Or as Fodor puts it:
…no theory of learning that anybody
has ever developed is, as far as I can see, a theory that tells you how concepts
are acquired; rather such theories tell you how beliefs are fixed by
experiences – they are essentially inductive logics. That kind of mechanism,
which shows how beliefs are fixed by experiences, makes sense only against the
background of radical nativism. (144).
Fodor and Chomsky (and most of the other participants at the
Royaumont conference I might add if the comments section is any indication)
believe that the above is a virtual tautology. All theories of learning are selective (i.e. stories where the given
hypothesis space proposes and the incoming experience disposes).[1]
Where tautology ends and (some of the) hard work begins is to specify the set
of projectable predicates that are in
fact biologically/cognitively given (i.e. the shape and content of the
hypothesis space that BFers actually bring to the “learning” problem). To repeat, no given space of alternatives, no way for an inductive logic or
theory of BF to operate. The account of what is given is (or is a very good
part of) a theory of the relevant biases.[2]
Fodor and Chomsky pull several important consequences out of
this tautology.
First, that many positions confidently explored in the
cognitive literature are strictly speaking incoherent as expressed. Fodor
discusses the “Piagetian” view that developmental conceptual change is a learning process in which learning
replaces earlier conceptually weaker stages with subsequent conceptually
stronger ones. Fodor argues that this
position is, very simply, conceptually untenable. It is not untenable that development involves a succession of stages
where the ith stage is conceptually stronger than the ith-1
stage. Rather it is untenable that this development is a result of stronger concepts arising via induction (i.e.
learning). Why, because for induction to be possible the conceptually stronger
system has to be representable. But to be representable means that the concepts
that represent it must be cognitively available (must already be in the
hypothesis space). But if so, they cannot enter the hypothesis space by
induction as they are already available for
induction. So, development cannot be a matter of CA via
learning.
Does this mean that we development cannot be a matter of
stronger concepts being acquired over time? No. But it does mean that this
process cannot be inductive (e.g. this scenario is compatible with “maturing”
new concepts, just not learning new ones).
Note too, that this is compatible with treating development as a matter
of new belief fixation. But recall that BF implies
that the relevant concepts are given and available for computational use. Or,
as Fodor puts it:
…a theory of conceptual plasticity
of organisms must be a theory of how the environment selects among the innately
specified concepts. It is not a theory of
how you acquire concepts, but a theory of how the environment determines which
parts of the conceptual mechanism in principle available to you are in fact
exploited. (151)
In other words:
…fixation of belief along the lines
of inductive logic…is one that assumes the most radical possible nativism: namely
that any engagement of the organism with its environment has to be mediated by
the availability of any concept that can eventually turn up in the organism’s
belief. The organism is a closed system proposing hypotheses to the world, and
the world then chooses among them in terms explicated by some inductive logic.
(152)
To repeat, Fodor and Chomsky and virtually all the
participants at the Royaumont conference take this to be tautological (as do
I). The only theories of learning we
have are theories of BF and these theories all presuppose that the stock of possible acquirable concepts is given.
Radical nativism indeed![3]
So far as I can tell, the logic that Fodor and Chomsky
outlined well over 30 years ago has not changed. And, if this is correct, then the central problem in cognition,
linguistics being a special case, is to adumbrate the relevant hypothesis space
for any given domain. And the only way to do this is to investigate the
acquirable in terms of the acquired and argue backwards. If BF is the name of
the game, then what is presupposed had better suffice to deliver the concepts
acquired, and once one looks carefully at what’s on offer, this simple
requirement appears to rule out most of the most popular theories, or so Fodor
and Chomsky (and I) would argue.
It is worth observing that this tautology was recognized by
the great empiricist philosophers. In
this sense, the blank tablet metaphor generally associated with their theories
of mind is unhelpful at best and misleading at worst. The distinguishing mark of empiricism is not
that the mind is unstructured (comes with no given hypothesis space) but that
the dimensions of the hypothesis space are entirely sensory. On this view, admissible concepts are either
sensory primitive concepts or Boolean combinations of such. This is a substantive theory, and, as Fodor
notes, it has proven to be false.[4]
Or as Fodor in his characteristic elegant way puts it:
I consider that the notion that
most human concepts are decomposable into a small set of simple concepts –let’s
say, a truth function of sensory primitives – has been exploded by two
centuries of philosophical and psychological investigation. In my opinion, the
failure of the empiricist program of reduction is probably the most important result of those two hundred years in the area of
cognition. (268)
As many of you know, Fodor has argued that not only is there
no possible reduction to a small number of sensory primitives, but that there
is very little possible reduction at all, at least when it comes to our basic
lexical concepts. I personally find his arguments against reductions rather
strong.[5]
However, whether one buys the conclusion, the form of the argument seems to me
correct: if you want a restricted set of primitives then you are obliged to
show how these can be used to build up what we actually observe. The empiricist
restriction to a small base of sensory primitives failed to deliver the goods, therefore, it cannot be correct; it
cannot be the case that our basic concepts are restricted to sensory
primitives.
So, is nativism ineluctable? Yup. So what’s the fight between Rationalists and
Empiricists about? It’s about two things: (i) the shape of the hypothesis
space: what are the primitive projectable predicates and how do they combine to
deliver more complex predicates (e.g. what are the basic operations, primitives
and principles of UG) (ii) how, given this space, are beliefs fixed (e.g. what
is the relation between PLD and G)? Everyone
is a nativist when it comes to CA. This is not
controversial (or shouldn’t be). Empiricists are nativists that believe in a
pretty spare hypothesis space. Rationalists are happy to entertain far more
complex ones. This difference has an
impact on how one understands BF. I turn to this in the next post.
[1]
The distinction between instructive and selective theories has a long history
in the study of the immune system. Here
is a useful summary. Fodor’s point, which seems to me to be entirely correct
(and obvious) is that all current
theories of learning are selectionist and hence presuppose a fixed innate background of relevant alternatives.
[2]
There may be room, in addition, for accounts of how to use incoming data to
update the information that guides a learners movements across the given
hypothesis space. What kinds of
evidential thresholds are there, how many competing hypothesis does one juggle
at once, what are the functions that in/decrease a hypothesis’ credibility
“score,” how many “kinds” of evidence are tabulated at once, does the
credibility function treat all hypotheses the same or are some more privileged
than others, etc.? These are all relevant concerns. But Fodor and Chomsky’s
tautological point is that they all are secondary to the issue of what does the
hypothesis space look like.
[3]
This conclusion is still resisted by many. See for example, Gallistel’s review
of Sue Carey’s book here.
Others
also seem to misunderstand the import of this. For example Amy Perfors (here)
claims that Fodor’s point is “true but trivial” (132). This is taken to be a
critique, but it is exactly Fodor’s
point. As Perfors emphasizes: “…any conception which relies on not having a
built-in hypothesis space is incoherent…” (128). This is a vigorous rewording
of Fodor’s and Chomsky’s point. It is
curious how often one finds strongly worded criticisms of nativist positions
followed immediately with these criticized positions offered as novel insights
by the very same author, in the very same paper.
[4]
Once again some have confused the issues at hand. Perfors (see above) is a good
example. The paper contrasts Nativism and Empiricism (127). But if everyone is
a nativist with respect to the requirement that for learning to be possible a
hypothesis space must be given, then everyone
must be a nativist, in Fodor and Chomsky’s sense. The debate is not over whether we are
nativists, but what kind of nativists we are (i.e. how rich a hypothesis space
are we willing to tolerate). The
contrast is between Rationalists and Empiricists, the latter limiting the
admissible predicates and operations to associationist ones. And, as Fodor
notes (see immediately below), this is what’s wrong with Empiricism. It’s not
the nativism, but the associationism that makes empiricism a failed program.
[5]
I hate to pick on the Perfors paper (well, not really) but it demonstrates how
cavalier critics can be when it comes to positions that they consider clearly
incorrect. The paper argues that Fodor’s
critique can be finessed by simply understanding that one can have hierarchies
of hypothesis spaces (132-3). Thus, contra Fodor, it is possible to treat
elements of level N as decomposed of concepts of level N+1 and this gets all
that Fodor criticizes but without the unwanted implicational consequences. Maybe. But oddly the paper never actually
illustrates how this might be done. You know, take a concept or two and
decompose them and show how they operate to license the wanted inferences and
block the unwanted ones. There are lots of concepts around to choose from.
Fodor has discussed a bunch. But the Perfors paper does nothing even
approaching this. It simply asserts that
conceptual hierarchies gets one around Fodor’s arguments. This is cheap stuff, really cheap. But sadly,
all too common.
