A big old bricolage. Philosophy (every kind, but nowadays I probably will only write on philosophy of x, where x is a science or mathematics (+retain some interest in meta-phil/meta-ethics)), leftish politics (but now weary of political pontificating), (post-Keynesian) economics (but now weary of economic theorising), palaeoanthropology, linguistics, history, natural history, ecology, and some (mostly old) writing of a more artistic kind, autobiographical and fiction (both mostly humorous).
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Showing posts with label Philosophy of Cognitive Science. Show all posts
Showing posts with label Philosophy of Cognitive Science. Show all posts
Monday, 15 May 2017
This book is an amazing piece of work
http://npu.edu.ua/!e-book/book/djvu/A/iif_kgpm_Foundations%20of%20Language.pdf
Monday, 17 April 2017
A Brief Philosophy of Biology Assignment where I Subtly Attack Singer and Review Recent Work on Human Altruism
Singer and the Evolution of Altruism
Biological
Assumptions in Peter Singer’s Ethics and
Intuitions:
In this 2005
paper, Peter Singer uses decades-old research in theoretical evolutionary
biology and some recent results in cognitive psychology and neuroscience to
argue that we should, in general, be highly suspicious of our intuitions when
engaging in moral reasoning, since they will tend to lead us astray from the
impartial application of abstract moral principles in favour of philosophically
indefensible ‘gut’ reactions.
In the first section of the paper, Singer argues that modern science
backs up many of the bleak descriptions of ‘human nature’ contained in the
works of Enlightenment philosophers like David Hume and Thomas Hobbes. Singer begins
the section by praising the following conjecture of Hume’s: “A man naturally
loves his children better than his nephews, his nephews better than his
cousins, his cousins better than strangers, where every thing else is equal” [Hume,
1739/1896: 251; Singer: 334]. Singer takes for granted that this is an accurate
observation, and gestures towards the Hamiltonian/Dawkinsian, gene-centric kin selection theory of altruism as the
explanation for it. Next, Singer begins to make some vaguely-scientifically-tethered
claims about prehistory: à la Hobbes, Singer asserts that early human life was “more
often a struggle for survival between different human beings” than a struggle
against other species [335]. This leads him onto a (once more) unsourced
account of the most general evolutionary theory for the origin of extra-genetic
altruism, reciprocal altruism; in
particular, he claims that “Many features of human morality could have grown
out of simple reciprocal practices such as the mutual removal of parasites from
awkward places” [336].
Finally, he refers to the empirical work of Jonathan Haidt on moral
rationalisation, and Joshua Greene’s very well-publicised studies on the
Trolley Problem, along with some neuroscientific studies about the link between
abnormalities in the prefrontal cortex and “anti-social behaviour”, to make
clear that there is a strong emotional element to the way we typically make
moral judgments, and no sense in which our intuitions are based on consistent
application of principle [339].
Singer uses all these considerations from disparate areas of scientific
inquiry for a methodological conclusion about moral philosophy: specifically,
he opposes his stance against John Rawls’ (fairly middle-ground) methodological
approach to moral reasoning, the principle of “reflective equilibrium” pioneered
in A Theory of Justice. Reflective
equilibrium is, in Singer’s words, the principle that “where there is no
inherently plausible theory that perfectly matches our initial moral judgments,
we should modify either the theory, or the judgments, until we have an
equilibrium between the two” [344]. Singer disagrees with this because he
thinks that it is often most rational often to ignore entirely our
pre-theoretic judgments (intuitions) when we encounter a moral dilemma. He
thinks that we should concern ourselves only
with applying the “plausible theory” (he more or less ignores the
complication that a moral theory wouldn’t be plausible in any sense if it ran
totally against our moral emotions). Crucially, he thinks the science lends a
lot of support to this methodological conclusion, since it shows that our intuitions
are not useful “data” when it comes to the process of rigorously reasoning
about what we ought to do, and lead us instead towards ethical ‘parochialisms’ and
inconsistencies.
Two Scientific Papers Examining
Evolutionary (including Multi-Level Selection)_Theories of Co-operation:
1.)
“Human Co-operation” (2013), by David Rand and Martin Nowak.
This paper is a discursive review of laboratory experiments
and field studies of human behaviour by a Yale cognitive scientist (Rand) and a
Harvard evolutionary biologist and mathematician (Nowak). It focusses on how
the empirical evidence bears on the relative strength of the five mechanisms
proposed to explain the evolution of human co-operation: direct reciprocity,
indirect reciprocity, spatial selection, multilevel selection, and kin
selection. The discussion in this paper relates directly to the vague
scientific references made by Singer towards theoretical evolutionary biology,
and his apparent belief that kin selection and direct reciprocity are the only
games in town.
In their very diplomatic treatment of
the evidence supporting each of the five mechanisms, Rand and Nowak seem to
suggest that there is good reason to suppose that all five mechanisms have played a role in the evolution of human
co-operation. Their analysis therefore doesn’t seem to support more hegemonic
views: for example, Hume’s strong claim about the disproportionate power of
familial affection (at least if “love” is interpreted in the broad sense that
Singer himself seems to want to interpret it). In fact, as Rand and Nowak
discuss in the section on multilevel selection, it has been experimentally shown
that unrelated strangers can be readily
induced to co-operate effectively with each other simply if they are told
they now ‘belong to a team’ in competition with another [Rand and Nowak,
419-420].
Singer, of course, is aware of
research on the power of group-loyalty and tribalism, as evinced by his
references to Jonathan Haidt. However, he seemed unware (in 2005) that this
well-studied phenomenon actually constitutes very good evidence for a kind of
(probably cultural) group selection towards within-group co-operation, thus
undermining purely gene-centric views about the evolution of human co-operation
(which tend to downplay the existence of widespread human co-operation).
2.) “The evolution of extreme cooperation
via shared dysphoric experiences” (2017), by Harvey Whitehouse et al (12
contributors).
This paper is a recent interdisciplinary research article
in Nature in which the authors lay
out a new mathematical model which they claim shows how “conditioning
cooperation on previous shared experience can allow individually costly
pro-group behavior to evolve”, with evidence provided in the form of the
testing of the predictions of the model in a range of sample populations
(including military veterans, college fraternity/sorority members, football
fans, martial arts practitioners, and twins) [1]. Overall, they obtain strong
support for the conclusion “that shared dysphoric experiences are a powerful
mechanism for promoting pro-group behaviors which under certain conditions can
be extremely costly to the individuals concerned” [6].
This finding doesn’t directly
undermine Singer’s biological assumptions in any direct way, although the
explanadum of the paper’s thesis (that humans sometimes engage in pro-group
behaviours which are “extremely costly to the individuals concerned” (like
suicide terrorism and fighting for ‘king and country’ in deadly conflicts [1]))
is something that Singer’s human-nature-related assertions in Ethics and Intuitions completely miss
out. Furthermore, one subsidiary empirical
conclusion of the article, used as evidence against the notion that
self-sacrifice for the group can be fully explained by the so-called
“psychological kin” phenomenon, does directly undermine one of Singer’s claims:
namely, the Humean one. As the authors
point out early in the piece, a recent survey of participants in the Libyan
uprising of 2011, thousands of whom died in combat, found that “frontline
fighters were more likely to choose genetically unrelated fellow
revolutionaries in preference to family as the group with which they are most
fused” [2].
Singer would probably argue that,
though these new results do impugn some parts of his generally vague scientific
discussion in Ethics and Intuitions, they
do not undermine the view that our moral “intuitions” can steer us away from a
more rational and universalised morality. Indeed, the idea that powerful,
large-scale co-operation tends to be group-based and highly context-dependent,
typically reliant on extreme events and highly dependent on the existence of enemy groups, only lends support to the
general thesis that we should try our best to transcend our more immediate
moral emotions in favour of the application of general principles. On the other
hand, it may be that Singer’s own distorted cognitive science has misled him as
to the real-world plausibility of a co-operative and altruistic ethic which
doesn’t rely psychologically on some kind of group identification. Singer may
well overlook the extent to which even non-parochial moral systems rely on the
commandeering of group-based moral sentiments; for example, achieving a
successful ‘expansion of the circle’ may require the stigmatisation of those
who don’t.
Bibliography
Rand, D.G. and
Nowak, M.A. “Human cooperation”, Trends
in Cognitive Sciences, Vol. 17: 8, August 2013, pp. 413-425.
[Google
citations: 348; Journal Citation Reports lists its 2013 Impact
Factor at 21.147.]
Singer, P.J. “Ethics and Intuitions”, The Journal of Ethics, Vol. 9: 3,
October 2005, pp. 331-352.
[Google citations: 460; Impact Factor of journal:
unavailable].
Whitehouse, H, et al. “The evolution of
extreme cooperation via shared dysphoric experiences”, Nature: Scientific Reports, 7, Article number: 44292, February 2017.
[Google citations: 1; Impact Factor of
journal: 5.228.]
Friday, 28 October 2016
AN ESSAY ON THE MYSTERIES OF THE MIND
Take Home Exercise for Philosophy of Mind and
Cognition
(b)Critically evaluate the arguments for the
Language of Thought and/or the Map Theory
In this essay, I examine the
arguments for the several stances it is possible to take in the ‘debate’ (largely
implicit) between the Language of Thought Hypothesis and the Map Theory of
cognition. My ultimate conclusion is that, whilst so many fundamental issues
are still extraordinarily unclear, there is one particular intermediate stance in this debate that has significantly more
weight behind it than any other.
I first discuss how, for
both hard-line connectionists (those who think that the brain undergoes no ‘classical
computation’) and hard-line Fodorians (those who think the key parts of cognition
will be explained only by classical computational models), the stakes between
the “Language of Thought Hypothesis” and “Map Theory” of cognition are quite
clear: if the LoTH is the right theory of all cognition, then the hard-line
connectionists are completely wrong, and if complex cognition occurs without
any real LoT, then the adherents of Fodor’s computational-representational
theory are completely wrong. I argue that both these poles are probably wrong,
but that the connectionist extreme is much less implausible than the Fodorian
one. I secondly explore the intricate intermediate position that that all (or
nearly all) cognition in non-human animals involves connectionist ‘software’,
captured by “Map Theory”, and yet that the Language of Thought theory
represents a classical ‘program’ run only by humans. This thesis has not been
actually expounded in any literature I am aware of, although it seems to me to
be the hypothesis that has the most weight behind it of all. As I argue, it is
highly concordant with Noam Chomsky’s carefully considered hypothesis (since
the mid-1990s) for the origin of the human language faculty/explanation for the
“Great Leap Forward”; the notion that productive thought is bound up with
productive language is supported by evidence from developmental psychology; the
notion that the vast majority of biological ‘software’ is connectionist is
strengthened by well-known considerations about the ‘hardware’ of the brain and
the nature of evolution; and finally, despite Fodor’s many protestations, it
seems to me that Prototype Theory is the best account of the nature of our
concepts, and Prototype-structured concepts are better explained in terms of
“Map Theory” than the “Language of Thought”.
In The Philosophy of Mind and Cognition, Frank Jackson and David
Braddon-Mitchell are careful not to hitch the Map Theory to the connectionist
programme in AI, or the Language of Thought to more ‘classical models of
cognition’. They note that the truth is much more complex and that it may often
be unclear whether a ‘classical’
program is being implemented in a connectionist substrate (indeed, they claim
that there might be no “source code” for the brain at all) [Braddon-Mitchell
& Jackson, 2007: 219]. Nevertheless, they do suggest a certain harmony
between connectionism and the “Map Theory”, and between classical computation
and Fodor’s LoT. This makes perfect sense, because a hard-line connectionist
cannot possibly accept the LoTH, and the Map Theory is explicitly proposed as
the one alternative to the LoTH.
Paul and Patricia
Churchland, the influential reductive neuro-computationalists, are probably the
most prominent proponents of what I’ve called ‘hard-line’ connectionism. For
several decades, the central philosophical claim of these two
neuro-philosophers has been that classical cognitive science is (and always has
been) on the wrong track, because the brain’s hardware is connectionist[1] and
we can only understand the brain’s ‘software’ by investigating the nature of
the hardware, rather than constructing abstract, simple models of rules and
representations which may have no “psychological reality”. In numerous articles
and papers from the late 80s onwards, the Churchlands have argued that evidence
from neurobiology[2]
makes it clear that the Language of Thought (which they tend to lump together
with ‘Folk Psychology’ as part of the one Fodorian package), even if apparently explanatory, simply doesn’t
exist [P.S. Churchland, 1986; P.M. Churchland, 1989; P.S. & P.M.
Churchland, 1990; P.S. Churchland & Sejnowski, 1990].
It is crucial to point out,
of course, that there was always a key weakness in the Churchlands’ critiques
of classical cognitive science and the LoTH – a weakness that would ultimately allow
Fodor to evade their attacks without working up too much of a sweat at all.
This key weakness was that the Churchlands didn’t attempt to provide a serious
alternative, connectionist-based theory
of thought (as opposed to mere detailed accounts of bio-chemical processes
correlated to certain kinds of cognition) to the one they so roundly rejected. The
absence of such a theory in the Churchlandian canon meant that it remained
justified for Fodor to simply repeat the famous remark he made in his seminal
1975 work: that the LoTH is “the only game in town” [1975: 406]. And as Fodor
and Pylyshyn pointed out in their influential 1988 critique of connectionism
(which includes extensive reference to the Churchlands), without such an
alternative account of the actual nature of thought,
the neurobiological evidence marshalled in supposed contradiction of the LoTH cannot nullify the
abductive argument, because the neurobiological details do not in themselves itself
constitute an explanatory science of the mind [Fodor & Pylyshyn, 1988]. As
Fodor and Pylyshyn emphasise in this same article, no connectionist can explain
productivity and systematicity except by creating “Classical architecture” in
connectionist models, yet these are the two key features of thought that form
the basis of Fodor’s argument to begin with [Fodor & Pylyshyn, 1988: 33-40].
Fortunately for the
connectionists, however, Frank Jackson and David Braddon-Mitchell’s “Map
Theory” does provide such an alternative account of the ultimate nature of
thought. Evidently, if such a theory is at all tenable, it lends significant
credence to the hard-line connectionists, because the very fact of its
existence destroys Fodor’s key abductive argument. And unfortunately for Fodor, it does indeed seem to me that the Map
Theory is plausible as an alternative theory of thought – in fact, highly
plausible. The idea of thought as involving highly structured, non-sentential, ‘nth’-dimensional
map-like representations actually possesses a number of virtues over the LoTH: it
is (at least intuitively) much more neatly reconcilable with connectionist
networks and the ‘hardware’ of the brain, since a map is an inherently
‘distributed’ structure; it gives a far more plausible account than the LoTH of
how it is that our beliefs about people, places and events can so fluidly
change as we have new experiences and take in new information (our mental
‘maps’ are simply updated); it seems to explain memory and memory-retrieval in
a much more plausible way than a Language of Thought, since it is not necessary
to claim that we have a vast number of propositions stored in our memory which
we can retrieve at will; it would appear to explain certain weaknesses we have
in formal reasoning (for example, why content seems to matter to our ability to
carry out tasks of reasoning with formally identical structure [Jackson,
Braddon-Mitchell, 2007: 235]); it appears to have evolutionary considerations
in its favour over the LoTH, since a Language of Thought is a highly elegant
computational system which seems at odds with the haphazard makeshift nature of
evolution (it seems unlikely that a LoT would be the kind of system to slowly
crystallise, and it seems highly unlikely that our ancient Cambrian ancestors
had a Language of Thought, whereas they might have had primitive ‘map-like’
representations); and it can account (seemingly) for “systematicity”, since the
‘places’ in the cognitive maps can be switched. All in all, therefore, the
Churchlandian position is, in my view, massively strengthened by the “Map
Theory”.
With that said, of course, the
reason that I do not think that the hard-line connectionist position is likely
to be right is that the Map Theory,
even if it does seem to account for systematicity,
it doesn’t quite answer Fodor’s productivity
criterion. As a result, it cannot explain the apparent infinite generative
capacity of human cognition – our ability to think an infinite array of discrete
thoughts by finite (combinatorial) means. As I am about to suggest, however, it
may very well be that only humans
have this full-strength productivity. This would imply that the Map Theory
might be a far more general account of biological cognition, and that the
hard-line connectionist position might be the correct one for all creatures on
Earth except us. As I’m about to argue, I think this is actually the most
plausible stance of all.
Perhaps the major consideration
in support of the view that only Homo
sapiens has a LoT in Fodor’s sense (with a combinatorial syntax which
allows for infinite productivity) is that it accords with Chomsky’s hypothesis
about the evolution of the language faculty. Whilst undoubtedly a highly
controversial hypothesis – disputed even by other notable generativists (for
example, Ray Jackendoff and Steven Pinker [2005]) – the conjecture does have
nontrivial theoretical and empirical backing.
Chomsky largely eschewed
speculation about the evolution of the language faculty for the first few
decades of the Universal Grammar research programme, but he has become quite
vocal in espousing his ‘spandrelist’ hypothesis about the evolution of the
“Faculty of Language” ever since he wrote The
Minimalist Program in 1995. The central idea of Chomsky’s “Minimalist
Program” is that it is possible to distil the ‘Universal Grammar’ into one basic
computational operation called “Merge”, with two forms, “External” (for
separate objects A and B) and “Internal” (for two objects where at least one
object contains the other) [Chomsky, 1995]. This lends credence to this
spandrelist hypothesis because of the elegant computational simplicity of such
a system (“like a snowflake”), and the fact that this computational procedure
subserves thought as fundamentally (or more fundamentally) as it subserves
language.
The most rigorous defence of
this evolutionary hypothesis appeared only recently, in a 2015 book Chomsky
co-authored with the MIT computer scientist, Robert Berwick, entitled Why Only Us? : Language and Evolution. In
this short work, Chomsky and Berwick specifically defend the thesis that this
“Merge” operation first originated by a single mutation in a human individual
around 80,000-100,000 years ago, which gave rise to recursion and hierarchical
structure in that individual’s thoughts [Chomsky & Berwick, 2015]. Whilst
they don’t invoke Fodor explicitly, it is clear that they see this as the
moment the “productivity” property key to Fodor’s LoT actually emerged (for the
first time in the history of life on the planet). They hold that this capacity
would have had some selectional advantage, and would have spread throughout the
population before being secondarily externalised [Chomsky & Berwick, 2015].
Much of the book is taken up by arguments in defence of an anti-adaptationist,
‘messy’ view of evolution as involving “stochastic effects” and both gradual
and sudden developments, with more at work than simple natural selection in simple
genetically varied populations. However, there are also a number of positive
considerations adduced in favour of the hypothesis, many of them (in my view) highly compelling.
Firstly, recursion appears
to be a property that is either absolutely present or absolutely absent, so seemingly
couldn’t come about as a gradual adaptation [72]. Secondly, there is strong
evidence (disputed by some) that no other species on the planet is capable of
recursive communication – birdsong, they claim, never gets further than “linear
chunking” or iteration of “motifs” [142]. Thirdly, the fact that human linguistic
externalisation is modality-independent (sign language has the same level of
syntactic complexity as spoken language, and is learnt as rapidly by children
in the right environment) seems to constitute good evidence that the Faculty of
Language was first a Faculty of Thought [74]. Fourthly, the sudden emergence of
productivity around 80,000 years ago appears to be one of the best possible
explanations for what Jarred Diamond famously called the “Great Leap Forward”
[37]. Fifthly, the extent of language variation in the world can seemingly
explained by the fact that the means of externalisation did not actually
co-evolve with the core computational system, but are instead much more ancient
systems being co-opted for the task [82]. Sixthly, the evolutionary timeframe
of the change is certainly not ruled out by the reconstructed genomic evidence used
to compare Homo sapiens with its ancestors and cousins [Chapter 4]. And, finally,
there is a neuro-anatomical hypothesis for what actually happened to create the
key “Merge” mutation – the dorsal and ventral “fiber tracts” linking different
language-related areas of the brain formed a ring (which does not exist in
birds) [Chapter 3].
There is also evidence from
developmental psychology that lends support to the idea that language is bound
up with a special form of thought that marks humans out as unique (and this
naturally holds even if Chomsky and Berwick’s hypothesis is a fair way off the
mark in terms of timeframe and suddenness of evolution). As Antoni Gomila notes
in a critical review of Jerry Fodor’s 2008 book The Language of Thought Revisited, “there is no evidence for the
systematicity and productivity of thought before the development of language,
at the end of the second year” [Gomila, 2011: 151]. Gomila cites the child
psychologist Elizabeth Spelke for this claim, whose experiments suggest that babies
are born with modular packets of knowledge of particular contents (physical,
numerical, biological, intentional), but that such knowledge does not admit of
productive combination before language – instead it is context-dependent and encapsulated
[Spelke, 2003]. It seems that the role of language in development is to create
interaction between these different modules.
Another major virtue of this
idea that the LoT is human-specific is that it means we can still maintain the
benefits of a largely connectionist view of biological cognition (those
benefits espoused by the Churchlands, in particular, general biological
plausibility (in terms of physiology and evolution)), and the advantages of Map
Theory as a general account of biological cognition. It only means that we have
to say that humans may be the only species with a ‘classical program’.
Finally, adopting the Map Theory
as an account of the majority of human thought also seems to work far better
for explaining the fuzzy nature of human concepts, described by “Prototype
Theory” in cognitive linguistics – the research programme pioneered by Eleanor
Rosch’s studies about ‘categories’ in the 1970s. Map Theory would seem to
suggest that concepts are not discretely structured, but form part of wider
cognitive architectures. If one accepts the tight connection between
connectionist software and Map Theory, then there is certainly reason to think
that Map Theory is highly compatible with Prototype Theory since, as Gomila
notes, connectionist models which are based on Prototype Theory have met with
increasing success since the 1990s [2011: 149].
Overall, I think that the debate
between Fodor’s Language of Thought Hypothesis and the “Map Theory” of
cognition raise deep and interesting questions about the nature of the mind
which are not currently soluble – although some possibilities seem distinctly
more likely than others. I think that the LoTH is extremely unlikely to be a
true theory of all cognition, and thus that the ‘hard-line’ Fodorians are
seriously misled. I think that the Map Theory, most naturally joined with
connectionist models, is far less implausible as a general account of the
cognitive architecture of biological creatures – however I think it fails to
account for productivity in humans. These considerations have ultimately led me
to the view that the most likely hypothesis is that Homo sapiens is the only species to possess a Language of Thought,
implemented as a ‘classical program’ on top of the connectionist hardware and
software that all biological organisms probably possess.
Naturally, I acknowledge
that this claim, despite the justifications I have given for it, is still an extremely speculative one. I am also
aware that I have an aesthetic bias
for this view: I think it is a beautiful notion that humans might be the only
creature with a classical program that was key for our success in colonising
the planet and reaching civilisation… So it might be totally wrong.
Reference List
Braddon-Mitchell, D and
Jackson, F. (2007), The Philosophy of
Mind and Cognition, 2nd edition, Blackwell Publishing.
Chomsky, N. (1995), The Minimalist Program, The MIT Press,
Cambridge, M.A.
Chomsky, N & Berwick, R.
(2015), Why Only Us? : Language and
Evolution, The MIT Press, Cambridge, M.A.
Churchland, P.M. (1989), A Neurocomputational Perspective: The Nature
of Mind and the Structure of Science, The MIT Press, Cambridge, M.A.
Churchland, P.M. and P.S.
(1990), Could a machine think? Scientific American 262
(1):32-37.
Churchland, P.S. (1986),
Neurophilosophy: Towards a Unified Science of Mind-Brain, The MIT Press,
Cambridge, M.A.
Churchland, P.S and Sejnowski,
T. (1990), “Neural representation and neural computation”, Philosophical
Perspectives 4:343-382.
Fodor, J. (1975), The Language of Thought, Harvard
University Press, Cambridge, M.A.
Fodor, J and Pylyshyn Z.
(1988), “Connectionism and Cognitive Architecture: A Critical Analysis”, Cognition 28
(1-2):3-71.
Gomila, A. (2011), “The
Language of Thought: Still a Game in Town?” Teorema: Revista
Internacional De Filosofía, 30(1), 145-155.
Jackendoff, P and Pinker, S.
(2005), “What's special about the human language faculty?” Cognition 95
(2).
Spelke, E. (2003), “What
Makes Us Smart? Core Knowledge and Natural Language”, en Gentner, D. & Goldin-Meadow,
D. (eds.): Language in Mind. Advances in
the Study of Language and Thought, The MIT Press, Cambridge, M.A., 277-312.
[1]
The most general and simplistic reason for thinking this is that sensory
neurons can be easily analogised to the input nodes in a connectionist model,
output nodes can be analogised to the motor neurons and the hidden nodes can be
analogised to the web of neural connections in our nervous systems
[Braddon-Mitchell & Jackson, 2007: 223])
[2] The
most straightforward data included the “distributed representation” used by the
brain (held to be strong counter-evidence of the existence of discrete symbols)
and the fact of “graceful degradation” (certainly counter-evidence of digital hardware).
Friday, 21 October 2016
Just an Essay Justifying "Universal Grammar" in a non-technical way
21. How successful, in your view, is Chomsky’s
attempt to interpret the theory of grammar as an investigation of a human
biological capacity?
The research programme that
Noam Chomsky began in linguistics, starting with the publication of his
monograph, Syntactic Structures, in
1957, and properly expounded in his 1965 work Aspects of the Theory of Syntax, is not very well understood by the
majority of its popular and even academic critics. Chomsky’s frequent failure
to hedge his claims about the postulated “language organ” (and his penchant for
overly strong pronouncements) has contributed to this failure of understanding,
since few critics bother to understand how he explicates these terms in his
methodological framework or where they sit in his metaphysics of mind. Of
course, at the same time, he has himself ignored some issues in biology that ought
to have compelled him to slightly change his tune on “innateness”. Nevertheless,
in this essay, I claim that, if one does properly understand the methodological
and philosophical foundations of the generative-grammar-based research
programme into the “Universal Grammar”, two things are evident: 1.) that the
programme has been about as successful as its progenitors hoped, if not more
(with no degeneration, in Lakatos’
terms), and 2.) that the programme has been successful in the independent sense
that it has led to genuine insights about the human mind.
One of the major things that
critics of ‘UG’ are wont to gloss over is that, strictly speaking, there is no
one “theory of Universal Grammar”. Instead, there is only a general ‘UG’-research programme based on the
construction of generative grammars held to capture the innate implicit knowledge
which is falsifiably (and each model
ought to be falsifiable individually) held to be required for the achievement
of human linguistic competence (the
generative grammar in the human mind).[1]
As this implies, the empirical support is (and could not be) uniform for ‘UG’,
understood as the UG-research programme;
instead, because the approaches to generative grammar that have been developed
as part of this overall research programme since Chomsky’s exposition of a
Transformational Grammar approach in Aspects
to the Theory of Syntax (1965) vary in the level of ‘innate’ ‘knowledge’
they postulate, different evidence is required to falsify each of these
approaches, and to confirm any one of them relative to the others. In
particular, a stronger version of the famous “Poverty of the Stimulus” argument
– one which draws on more evidence of linguistic universals, infant reliance on
rules and hard-to-empirically-explain examples of “structure-dependence” – are needed to support the early Transformational
Grammar models than for the models proposed since the Principle and Parameters
paradigm shift, with the Minimalist Program starting from the postulation that the
generative system is simpler than a grammar
(per se), and therefore probably being more prone to rejection by evidence
of too many universals and such (this
would, of course, be rejection relative to another model of generative grammar).
It is very important to
acknowledge, of course, that there are some very sensible philosophical critics
of the UG research-programme, like the Australian-born philosopher of biology,
Fiona Cowie [1999], who see Chomsky’s very use of the word “innate” as problematic from a scientific viewpoint. One of
Cowie’s motivations for her, in the end, quite moderate critique of “nativist”
theories in What’s Within? is the
fact that the word has no clear scientific interpretation. She shares this view
with her fellow philosopher of biology, Paul Griffiths (of the University of
Sydney), who in his 2002 paper “What is innateness?” points out that the word
“innate” is no longer used in any field of biology except cognitive science,
and argues that it ought to be discarded in cognitive science, too, since
innateness is a “folk-biological” concept which yokes together three biologically
separate notions: species-typicality, developmental fixity and intended design
[Griffiths, 2002: 2].
Whilst I myself agree with
this critique, I do not think it is in the least bit destructive of Chomsky’s
research-programme, because I also think (and Griffiths does not explicitly
deny) that the generativist talk of an “innate language faculty” can simply be substituted
for one of two other phrases: a “developmentally canalised, species-typical
language faculty” (in the case of Chomsky and his fellow non-adaptationists (spandrelists)
about the evolution of the language faculty) or “an adaptive, environmentally canalised, species-typical language
faculty” (in the case of Pinker, Jackendoff and the other adaptationists about the
evolution of the language faculty).[2] One
small criticism I have of Chomsky (along with fellow generativists like Charles
Yang, Robert Berwick, Steven Pinker, Ray Jackendoff, etc) is that he hasn’t made
this terminological alteration himself, still using the language of Cartesian
or Humboldtian rationalism, of which he has always regarded his work a direct descendant [Chomsky, 1965, 1986]. However, since I don’t think that the use of
this unscientific language is a significant problem for the UG-research
programme, I will myself, in the rest of this essay, always type the folk term in
single inverted commas while still assuming that I am defending Chomsky.
Past this terminological
hurdle, the single biggest reason why I think that Chomsky’s research programme
has been a success in both the senses I outlined in my introduction is empirical validation. It seems to me
quite clear that the theory that Homo
sapiens does have a developmentally canalised, species-typical language
faculty has not been falsified over
the decades, but is instead clearly still the best (indeed, the only)
explanation for the empirical evidence of rapid language acquisition and human
linguistic competence.
Despite the impression evoked
by some critics, Chomsky’s generative research-programme did not begin as a scholastic,
a priori enterprise, but was motivated
by empirical considerations of a fairly fundamental kind. The reason that Chomsky’s
famous 1957 monograph, Syntactic
Structures, is often heralded as the founding document of modern cognitive
science, despite not framing itself as a work of mentalistic investigation (and
containing no argument for the existence of an ‘innate’ “language faculty”) is
that Chomsky’s formal conclusions in SS
directly entail the powerful scientific conclusion that at least one language
(English) cannot be understood in behaviourist terms, and that English speakers
must ‘possess’ (in some vague sense, leaving representational and acquisitional
issues aside) what Chomsky would later call, in Aspects of the Theory of Syntax, “a system of generative processes”
[1965: 4]. The most pivotal part of
Chomsky’s monograph is his chapter 3 proof
that a finite-state or Markov model (a model which involves the
mono-directional chaining of words) is simply inadequate to generate all the grammatical sentences of English,
and the implication, explored in the next two chapters (“Phrase Structure Grammar”
and “Limitations of Phrase Structure Description”, in which he introduces the
notion of a “transformation” to complement the inadequate phrase structure
grammar), that an adequate generative grammar must be a hierarchical or syntax-based grammar
of some kind.[3]
Although the inadequacy of the finite-state model perhaps should have been
obvious, it was no trifling result, because it refutes the strongest empiricist
view about language production. If it is impossible to formally generate English sentences by a finite-state model, then
it is also impossible to generate English sentences by the kind of finite-state
model one might want to implement in a computer, or one might imagine existing
in a brain: a complicated word-chain device relying on transitional probabilities. One instead needs generative principles, and this fact literally precludes the strongest empiricist
understanding of language production.[4]
Evidently, behaviourists
wanted to avoid talking about mentation at all, but the theory of language
production found within works like Skinner’s Verbal Behavior (the subject of Chomsky’s famously destructive 1959
review) clearly rules out the
possibility that human language is produced by a generative grammar. As Steven
Pinker writes in The Language Instinct, the
finite-state model is directly “congenial to stimulus-response theories: a
stimulus elicits a spoken word as a response, then the speaker perceives his or
her own response, which serves as the next stimulus, eliciting one out of
several words as the next response, and so on” [1994: 93].
Of course, in Syntactic Structures itself, Chomsky uses his chapter 3 proof to
motivate a more purely methodological conclusion: that linguistics ought to shift
from static, structural description of corpora – the behaviourist methodology
of American Structuralism[5] – towards
the construction of the kind of descriptively adequate generative grammar he
attempts to construct for English in SS
(a transformational phrase structure grammar). Yet it is not hard to see how this
led to the far bolder scientific shift expounded in Aspects of the Theory of Syntax. In order to make the case for an
entirely new vision of linguistics in Aspects,
Chomsky extended his insight about the necessity of a creative model for English sentence-production
into all languages (on the strongly empirically
based contention that no other human language can be adequately described by a
finite state model either, supplemented by the empirically based assumption of strong
human cognitive universality), and combined this with an argument in support of
(essentially) 18th Century Rationalism. His new claim was that the
aim of the discipline should be to construct generative grammars that are descriptively
adequate for all natural languages, and explanatorily
adequate as “universal grammars”. That is to say, linguists should attempt
to describe the ‘innate’ linguistic competence or “system of generative
processes” held to be necessary for the acquisition of any natural language by
a child [1965: 6].
At this point, I should
point out that, whilst I am claiming that Chomsky’s research-programme was empirically
motivated at its inception, I am not claiming that all its empirical
presuppositions were thoroughly confirmed in 1965. It clearly might have been the case that the
evidence collected after 1965 strongly disconfirmed these empirical
presuppositions, and thus rendered the research programme untenable. If it had
turned out that there were
significant cognitive group-differences in Homo
sapiens – that some populations don’t have (and couldn’t have) language
with any recursion (as Daniel Everett claimed to show, falsely[6]) – then that would be a kind of
falsification of the universalist aspect of the programme (although,
presumably, that wouldn’t sound the death-knell for the investigation of the
linguistic competence of the human populations with the developmentally
canalised language faculty). Similarly, if “Nim Chimpsky” (or, for that matter,
some other animal) had proven capable of learning actual grammar, rather than
mere sign-strings, then that would have been a blow to Chomsky’s pretty
significant working assumption that the language faculty is unique to humans
(and it would probably have forced him to attribute to the ‘language faculty’ a
lower degree of developmental canalisation).
More interestingly, it might
have been the case that the evidence gathered after 1965 strongly favoured the hypothesis
that language acquisition occurs by means of solely domain-general cognitive processes, as Michael Tomasello’s
“usage-based theory of language” holds (a theory of language which, despite its
domain-generality, avoids getting wrecked on Chomsky’s SS proof about the inadequacy of Markov word-chains by positing that
speakers learn entire grammatical constructions
by means of a powerful “theory of mind” and contextual-awareness) [Tomasello,
2003]. If it had turned out that the condition known as “Specific Language
Impairment” was in all cases actually just a misdiagnosed general cognitive impairment,
or that all fully articulate older children diagnosed with autism or an
autism-spectrum disorder have either been misdiagnosed or had full cognitive
empathy in the critical period for acquisition, then that would lend strong
support to a Tomasello-type theory over one which postulates a language
faculty.
As it stands, however, things
have not turned out this way. Thus, the UG-research programme has been
completely justified in continuing to exist and grow.
In more recent years, some subtler empirical objections
to the UG research-programme have come from the AI community, which has had far
more success with trained statistical models (for example, probabilistic context-free grammars) than categorical models (any
of the ‘pure’ models created by generativists). The schism between these two
worlds – one practical, one theoretical – came to the fore in 2011 after
Chomsky made some highly disdainful comments about statistical approaches to “various
linguistic problems” (accusing statistical modellers of doing ‘butterfly-collecting’
rather than “science”) at the Brains, Machines and Minds symposium held on MIT’s
150th Anniversary. Soon after, the Director of Research at Google,
Peter Norvig, published an essay on Chomsky online in which he argued that the
father of linguistics was entirely in the wrong, since probabilistic models
have been far more successful in actual implementations than any categorical
ones [Norvig, 2011]. Nevertheless, as Chomsky’s student Charles Yang has argued
in response to similar critiques, whilst there is now “a good deal of evidence
against the ‘triggering’ model of learning” (which, Yang happily concedes, deserves
to be replaced by a “probabilistic model”, which is domain-general) “one
needn’t, and shouldn’t, abandon the categorical theory of GRAMMAR”, which is
domain-specific [Yang, 2007: 215]. In other words, it is still perfectly cogent
to study the abstract generative processes, because, as Chomsky has always
claimed, they represent the underlying linguistic
competence and nothing more.
There is one kind of critique of Chomsky’s
research-programme which has nothing to do with the empirics of ‘UG’, but the metaphysics. Towards the end of her
critique of ‘UG’ in What’s Within? Fiona
Cowie brings up an objection of exactly this metaphysical kind. Tapping into a
broader philosophical doubt many hard-line connectionists and ‘Churchlandian’ eliminativists
have about the computational theory of mind in general, Cowie claims that it is
deeply problematic that Chomsky cannot specify what the implicit “knowledge of
language” [7]
he theorises about actually is [Cowie,
1999: 274]. In particular, it is unclear, she claims, in what sense grammar
actually could be “represented” [1999: 274].
Despite the seeming
importance of this line of objection, Chomsky is simply a deflationist about
this question of “representation”, and I think he is right to be so. The reality
is that there is no possible theory of linguistic-competence – no possible explanatory scientific theory of
language – other than one which posits ‘knowledge’ in the form of a system of
“rules and representations” [Chomsky, 1980]. This means that Chomsky’s UG
research-programme is the only possible scientific research programme into the
faculty of language. The fact that, as Chomsky himself says in a reply to the
philosopher Georges Rey (quoting Randy Gallistel) “we clearly do not understand
how the nervous system computes,” or even “the foundations of its ability to
compute,” should not put a halt to the only scientific investigation into the
human language faculty, just as it shouldn’t put a halt to any other cognitive
scientific studies (including in other species) [Chomsky in Chomsky and his Critics, 2003: 276]. As
Chomsky says in that same reply, “surely no one expects that some isolable part
of the organism is dedicated to digestion, or navigation, or language, or any
other component that is singled out for investigation in any rational approach
to the study of a complex system” [Chomsky, 2003: 276].
In
summary, I believe that Chomsky’s attempt to interpret the theory of grammar as
an investigation of a human biological capacity has been highly successful, according to any reasonable criteria
for such things. The Universal Grammar-research programme he began in the early
1960s has enjoyed significant internal development while its core presuppositions
have been strongly confirmed. This has, in turn, revealed to us important
insights about the human mind.
[1] Of
course, the “theory of Universal Grammar” might then be understood as the empirical
presuppositions necessary for the tenability of this programme in general.
However, across the history of
the UG-research programme, it seems to me that the only constant empirical presuppositions
are: 1.) human cognitive universality (no significant cognitive group-differences
in Homo sapiens), and 2.) the
existence, in all humans without severe impairment, of a developmentally canalised,
domain-specific, computational ‘module’ (in the vaguest possible sense) which
explains human “linguistic competence” (and possibly several other human
abilities) for which we can construct generative models (not even grammars per
se) by investigating the syntax of the world’s languages. It seems to me that many
critics who mount general attacks on “Universal Grammar” believe they are
attacking a stronger thesis than the conjunction of these two propositions.
[2] Strictly speaking, it would be best
to rephrase Chomsky’s usage of “innate language faculty” with “a
developmentally canalised, species-typical language faculty which originated as
a spandrel but proved adaptive and was then selected for” [Chomsky, 2012: 14].
[3] He doesn’t use the word “hierarchical”
in SS.
[4] Of course, this in itself shows
nothing about the ‘innateness’ (more properly, developmental canalization, etc)
of the generative processes necessary for language production in an adult
speaker. In itself, it also clearly doesn’t rule out the possibility of
probabilistic language models more sophisticated than Markov chains (i.e.
probabilistic generative grammars), or, arguably, Michael Tomasello’s
usage-based theory of language [2003], which I’ll discuss later.
[5] Of which one of the major proponents
was Chomsky’s teacher and mentor, Zellig Harris.
[6] Pirahã
does have recursion, and (more fundamentally) Piraha speakers can learn
Portuguese, so Everett’s ‘argument’, such as it is, poses no problem for the
research programme at all [Nevins, Pesetsky, Rodrigues: 2009].
[7] Which
he has tried to re-term the “cognizance of language” in an attempt to stop the
philosophical controversy.
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