Shortly after our walk began, Nancy noticed an elegant old doorway
which drew us near. At the time, we had
been marvelling at the narrow alleyways, cobblestone roads, and ornate old
buildings; this doorway (shown below) was another amazing sight on our walking
tour.
However, a plaque by the doorway heightened
our interest in it. This was the
location of the house in which philosopher Rene Descartes lived in the final
year of his life. Descartes had come to
Stockholm in 1649 to be the philosophical mentor of Queen Christina. However, to fit her schedule, Descartes (a
notorious late riser) found himself walking from here to the palace (a few
minutes away) for 5 am philosophical discussions. The chilly walk, and cold castle, led to
pneumonia which killed Descartes in 1650, only a few months after his arrival
in Sweden. (An alternative theory
provided by Cartesian scholar Theodor Ebert is that Descartes
was poisoned by a Catholic priest who used a communion wafer laced with
arsenic.)
This surprising plaque provided a delightful historical context for our walk – Descartes lived here! – but, later, made me reflect upon Descartes’ impact on cognitive science in general, and on my own training in particular.
Classical cognitive science, which
views cognition as the rule-governed manipulation of symbols, is largely the
modern face of Cartesian philosophy.
Descartes’ view that one acquires new knowledge via reasoning from
axiomatic knowledge is completely consistent with the classical view that
cognition is computation. In my new book
(which
will be released within the next few weeks), I suggest that the critical
difference between classical cognitive science and Cartesian philosophy is that
the former replaces the latter’s dualism with materialism.
As a PhD student I was steeped in
the classical approach while being trained in the fabulous environment created
by my supervisor, Zenon Pylyshyn. My
thesis concerned computational vision, and I spent a fair amount of time
working through mathematical proofs concerning natural constraints that could
be used to solve certain problems facing human motion perception. Such computational investigations are clearly
consistent with the spirit of Cartesian philosophy.
When I arrived at the University
of Alberta in 1987, I was faced with the task of developing my own research
program. To pay the bills, I continued
with some work on computational vision.
However, I also began to steep myself in connectionist cognitive
science, primarily with the goal of critiquing it. To my surprise, I made a handful of
discoveries that made me more sympathetic to it. In some sense, I was replacing the influence
of Rene Descartes with that of John Locke!
Later work on interpreting artificial neural networks permitted me to
flesh out some key similarities between classical and connectionist cognitive
science, similarities that served as the foundation of my
first book. Artificial neural
networks are involved in the majority of my publications; they reflect an
empiricist philosophy that is difficult to reconcile with Cartesian
rationality. Interestingly, though, I am
reluctant to think of myself as a connectionist.
More recently I have become very
interested in the central ideas of another school, embodied cognitive
science. In terms of the era of
Descartes and Locke, embodied cognitive science has roots in the philosophy of
Giambattista Vico. My students and I
explored embodied cognitive science using some simple
LEGO robots. One result of this has
been my openness to considering the virtues of situation and embodiment.
It would seem that my development
as a cognitive scientist has taken me a long distance from my classical
training; the phrase “Descartes lived here” describes the evolution of my own
beliefs about cognitive science.
However, I have not completely
abandoned my classical roots. I still
see a great deal of merit in the core assumptions of classical cognitive
science. My soon-to-be released book
makes an effort to find links amongst the foundations of classical,
connectionist, and embodied cognitive science.
I argue that these three approaches are not as incommensurable as one
might imagine. To the extent that my
personal cognitive science can be represented as the cobblestone alleys of
Gamla Stan, Descartes still walks there – perhaps softly.