How Can We Possibly Tell If It’s Conscious?
April 18, 2002 by Ray Kurzweil
At the Tucson 2002: Toward a Science of Consciousness conference, Ray Kurzweil addressed the question of how to tell if something is conscious. He proposed two thought experiments.
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.
- “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:
– Most of our cells turn over within a month or a few months.
– 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:
– He would have all of the same abilities to understand his own situation, the same feedback loops.
– The activity in his nonbiological brain would be comparable to Ray 1.
– He would be completely convincing to Ray’s friends.
– 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…
- Our ultimate reality is our pattern.
- Knowledge is a pattern as distinguished from mere information.
- Losing knowledge is a profound loss.
– Losing a person is a profound loss.
- Patterns persist.
– The pattern of water in a stream
- 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.