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. ...  In 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 1950)
• REPLY 2: "However, this is mere speculation. I am not very impressed with theological arguments whatever they may be used to support. Such arguments have often been found unsatisfactory in the past." (Turing 1950)

The Importance of Biology

1. perhaps only biological means will suffice
2. perhaps machines need to have life experiences and not just preprogrammed responses
• Turing's "child machine" proposal
• Connectionism & the embodied approach would suggest this too
3. Searle's "biological naturalism": speculates that something noncomputational accounts for the brain's consciousness

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 items
• 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 speaking program.
• 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 "hearing"
• Conclusion: computation is not sufficient for conscious understanding.
• LH: Note the similarity of this experiment to "Leibniz's mill"

From Non-Computability to Quantum Consciousness

• The mathematical objection: humans have supercomputational mathematical abilities.
• presumably this is related to consciousness.
• Penrose speculates that these abilities are due to quantum effects
• 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 function." (207)
• "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."