Robot ConsciousnessRobot Consciousness
smells, warmth, and colors, are found only in us, as sentient beings, and not in external objects.
The non-sentient world consists, he thought, merely of aggregates of tiny bits of matter with
so-called primary (mechanical) properties like size, shape, location, motion, and contact. He
outlined, quite presciently, how contact between these particles and our sense organs evoke sec-
ondary (conscious) properties in us such as the redness we see or the pain that we feel. But why
should these secondary properties be produced in sentient beings? Galileo’s direct intellectual
descendants, Hobbes and Descartes, answered this question in vastly different ways.
Hobbes (1651/1958) adopted the Galilean view of nature and sensation, but he was more
explicit in claiming that even we sentient beings consist only of bits of matter with primary prop-
erties. Secondary properties, he claimed, were somehow produced by these, specifically by the
mechanisms of the brain, though he had no adequate theory as to why or how this occurs.
Descartes (1647/1988) agreed with Hobbes that the external world and human bodies con-
sist only of tiny bits of matter, but to solve the mystery of how brains and consciousness are
related he offered a mix of science and Christianity, a dualism of matter and soul. He claimed
that the conscious mind exists outside of the natural realm and, like a drone pilot, controls and
receives feedback from the human body via a tiny gland, a biological antenna of sorts, deep in
the brain.
While Descartes is famous for his attempted knock-down deductive arguments in favor of
mind/body dualism—in particular, his arguments assuming that the mind cannot be doubted
and has no spatial extent—here his inductive arguments (1637/1988) hold far greater rel-
evance. One involves a viva voce (live voice) test for distinguishing minded beings from mere
mechanical entities such as humanoid contrivances (in essence, robots) and lesser animals like
parrots and apes. He claimed that if one attempted to converse with these entities, one would
quickly find that they have a finite verbal repertoire, whereas we humans can sensibly engage
in open-ended conversations about countless topics. There is, he suggests, no possible way that a
finite machine could exhibit this kind of infinite conversational ability. In humans, therefore,
the best explanation for the mind behind the conversational ability is that it is a non-mechan-
ical, spiritual substance. Descartes offered a parallel argument regarding our seemingly unique
and boundless, so-called (remember this term) universal power to reason about countless dif-
ferent scenarios.
Decades later, Leibniz also despaired of a mechanical explanation for conscious experience.
He wrote:Moreover, it must be confessed that perception and that which depends upon it are
inexplicable on mechanical grounds... And supposing there were a machine, so con-
structed as to think, feel, and have perception, it might be conceived as increased in
size, while keeping the same proportions, so that one might go into it as into a mill.
That being so, we should, on examining its interior, find only parts which work one
upon another, and never anything by which to explain a perception.
(1714/1968: 4)Put plainly, view my living brain through a microscope or any other instrument at any level
of magnification and you will find nothing in there indicating an experience of blue wrist
restraints or of the pain I feel as I try to writhe free. Indeed, many contemporary philosophers
and neuroscientists think that Leibniz was basically right. Advances in microscopy and neuroim-
aging have made Leibniz’ Mill a reality, and yet, it seems, we are no closer to cracking the mys-
tery of how neural machinations produce those distinctive qualities of consciousness experience,
qualia as they are now called.