Chapter 14: Could a Machine be Conscious?
- The brain is a machine. It
is a conscious machine. ... So of course some
machines can think and be conscious. Your brain and mine, for
example. (Searle 1997: 202)
Conscious Machines are Impossible
- [Descartes argument: machines are only finitely capable;
consciousness/intelligence is an infinite capability; therefore
machines can't be conscious.]
- Religious considerations enter here.
Souls, Spirits, and Separate Minds
- OBJECTION: "Thinking
is a function of man's immortal soul. God has given an immortal
soul to every man and woman, but not to any other animal or to
machines. Hence no animal or machine can think". (Turing 1950)
- REPLY 1: "[T]he argument
quoted above implies a serious restriction of the omnipotence of the
Almighty ... but should
we not believe that He has freedom to confer a soul on an elephant if
He sees fit? We might expect that He would only exercise this power in
conjunction with a mutation which provided the elephant with an
appropriately improved brain to minister to the needs of this soul. An
argument of exactly similar form may be made for the case of machines.
attempting to construct such machines we should not be irreverently
usurping His power of creating souls, any more than we are in the
procreation of children: rather we are, in either case, instruments of
His will providing mansions for the souls that He creates." (Turing
- REPLY 2: "However, this is mere speculation. I am not very
with theological arguments whatever they may be used to support. Such
arguments have often been found unsatisfactory in the past." (Turing
The Importance of Biology
- perhaps only biological means will suffice
- perhaps machines need to have life experiences and not just
Searle's "biological naturalism": speculates that something noncomputational accounts for the
- Turing's "child machine" proposal
- Connectionism & the embodied approach would suggest this too
Machines Will Never Do X
- X = "Be kind, resourceful, beautiful, friendly ... have
initiative, have a sense of humor, tell right from wrong, make mistakes
... fall in love, enjoy strawberries and cream ... make someone fall in
love with it, learn from experience ... use words properly, be the
subject of its own thought ... do something really new." (Turing 1950)
- Two questions
- is the prediction true: prospects are mixed for these various
- is the thing computers supposedly can't do really essential to intelligence?
- most things on the list fail on this score
- an unkind, unresourceful, ugly, unfriendly, human slacker
without a sense of humor is still a conscious being.
- Free will: "Lady Lovelace's objection"
- "The analytical engine has no pretension to originate anything. It can
do whatever we know how to order
it to perform."
- Nub of it: machines can't be original or creative?
- Unless the presumption of consciousness is already built into
your notion of creativity it seems hard to deny the creativity
computers in some connections.
- striking example of connectionist networks: "the ANN works
[things] out for itself, and even its creators cannot know exactly how
it did it or what the weights [to which its connections have trained
up] mean." (SB: 188)
The Chinese Room
- Imagine you (who speak only
English) were acting as the CPU of a Turing Test passing Chinese
- You implement the program by following a set of instructions
written our in English.
- You wouldn't thereby understand -- in the sense of being
conscious of the meanings of -- the Chinese "you" were "speaking" and
- Conclusion: computation is not sufficient for conscious
- LH: Note the similarity of this experiment to "Leibniz's mill"
From Non-Computability to Quantum Consciousness
- The mathematical objection: humans have supercomputational
- presumably this is related to consciousness.
- Penrose speculates that these abilities are due to quantum
- SB's explanation Roger Penrose's explanation of the quantum
conundrum: "there are two levels of explanation in physics: the
familiar classical level used to describe large-scale objects, and the
quantum level used to describe very small things. Both these
levels are completely deterministic and computable. The trouble
starts when you move from one to the other. At the quantum level
superposed states are possible. That is, two possibilities can
exist at the same time, but at the classical level either one or the
other must be the case. When we make an observation (i.e.,
working at the classical level) the superposed states have to collapse
into one or other possibility, a process known as collapse of the wave
- "Some physicists ... have claimed that consciousness causes the
collapse of the wave function" (208).
- The Hammerhoff Penrose thesis: "consciousness emerges from
quantum coherence in the microtubules." (208)
- Penrose suggest that these quantum effect may induce a
time-warp that accounts for Libet's finding of a .5 second
delay in consciousness.
- Grush and Churchland (1995): "the argument consists of merest
possibility piled upon merest possibility teetering upon a tippy
foundation of "might-be-for-all-we-know's ... we judge it to be
completely unconvincing and probably false."