Excerpted from a slide presentation at Tucson 2002: Toward A Science of Consciousness
April 10, 2002
Thought Experiment 1: Create Ray 2

• Make a copy of all the salient details of me.
• Ray 2 has all of my memories, so he remembers having been me.
• He recalls all of my memories.
• If you meet him, you would be convinced he is Ray (he passes a “Ray Turing Test”).
• You could do this while I was sleeping, so I may not even know about Ray 2.
• If you tell me that we don’t need Ray 1 anymore, I may beg to differ.
• I may come to believe in Ray 2′s existence, but I would consider him “someone else.”.
• Ray 2′s continued existence does not represent immortality for me.
• Copying me does not transfer my consciousness because I’m still here… Okay, so far so good.

Thought Experiment 2: Gradual Replacement of Ray

• Replace a tiny portion of my brain with its neuromorphic equivalent.
• Okay, I’m still here… the operation was successful (eventually the nanobots will do this without surgery).
• We know people like this already (e.g., people with cochlear implants, Parkinson’s implants, other neural implants).
• Do it again… okay I’m still here… and again…
• At the end of the process, I’m still here. There never was an “old Ray” and a “new Ray”. I’m the same as I was before. No one ever missed me, including me.
• Gradual replacement of Ray results in Ray, so consciousness and identity appears to have been preserved.
• HOWEVER…

However…

• “Ray at the end of the gradual replacement scenario” is entirely equivalent to Ray 2 in the mental porting scenario.
• “Ray at the end of the gradual replacement scenario” is not Ray but someone else.
• But in the gradual replacement scenario, when did Ray become someone else?
• The gradual replacement scenario is entirely equivalent to what happens naturally:
  &nbsp&nbsp – Most of our cells turn over within a month or a few months.
  &nbsp&nbsp – Those that persist longer (e.g., neurons) nonetheless replace their particles.
• So are we continually being replaced by someone else?

This is a real issue wrg Cyronics

• Assuming a “preserved” person is ultimately “reanimated,” many of the proposed methods imply that the reanimated person will be “rebuilt” with new materials and even entirely new neuromorphically equivalent systems.
• The reanimated person will, therefore, effectively be “Ray 2” (i.e., someone else).

There is no objective (third party) test for subjectivity (first person experience aka consciousness)

• If Ray 2 happens to be nonbiological:
  &nbsp&nbsp– He would have all of the same abilities to understand his own situation, the same feedback loops.
  &nbsp&nbsp– The activity in his nonbiological brain would be comparable to Ray 1.
  &nbsp&nbsp– He would be completely convincing to Ray’s friends.
  &nbsp&nbsp– But there is no way to experience his subjective experiences without making philosophical assumptions.
• Machines today are not convincing, but they are still much simpler than human intelligence.
• But this gap will be closed, and future machines will be “convincing” in their emotional intelligence.
• But there remains an inherent objective gap in assessing the subjective experience of another entity.

The “Hard” Issue of Consciousness

• Only becomes a scientific question when one makes certain philosophical assumptions.
• Some people conclude that consciousness is an illusion, that there is no real issue.
• Consciousness is, therefore, the ultimate ontological question, the appropriate province of philosophy and religion.
• So my philosophy is…

… Patternism

• Our ultimate reality is our pattern.
• Knowledge is a pattern as distinguished from mere information.
• Losing knowledge is a profound loss.
  &nbsp&nbsp– Losing a person is a profound loss.
• Patterns persist.
  &nbsp&nbsp– The pattern of water in a stream
  &nbsp&nbsp– Ray
• We are still left with dilemmas because patterns can be copied

We will ultimately come to accept that nonbiological entities can be (are) conscious

• But this is a political and psychological prediction.
• There is no way to demonstrate this without making philosophical assumptions

You all seem conscious, but

• Maybe I’m living in a simulation and you’re all part of the simulation.
• Or (at the end of the conference), perhaps I only have memories of you, but the experiences never actually took place.
• Or, maybe I am only having a conscious experience of recalling memories of you but neither you nor the memories really exist.
• Or, perhaps…

Ray Kurzweil’s The Law of Accelerating Returns essay includes further discussion of these issues about consciousness.