Steven Pinker is a psychologist and linguist. He is a professor at Harvard. He has written many books and he could be called one of the optimists on intellectual landscape. His books are popular and some of those books explore how brain works and other aspects of human mind.

David Deutsch is a physicist and philosopher. He is known for his work in the field of quantum computing and the theory of parallel universes. His book "The Fabric of Reality" is widely regarded as a seminal work in the field of theoretical physics. He can also be called someone who is an optimist.

The Joe Walker Podcast

The discussion between these two happened on the Joe Walker Podcast. You can see the entire discussion here: https://www.youtube.com/watch?v=3Ho-vJZsMgk

Summary of the discussion

On AGI

Deutsch was more optimistic and thought that this is achievable in near term and is a natural next step. Pinker on other hand had doubts if whether this is possible or more importantly, desirable. He seemed to think that AI that is good at specialized tasks might be sufficient.

Risks of AI

Deutsch and Pinker both acknowledged the risks. Deutsch was of opinion that a sentient machine is vastly beneficial to humanity compared to the risks where as Pinker was more concerned about existential risks posed by such AI.

Implications for human society

Deutsch calls for embracing the progress that AI will bring. He is optimistic that AI will not pose much of a threat to human society. Where as Pinker advises caution and says we must apply critical thinking and evaluate how each AI advancement impacts our human society and social values.

On consciousness

Deutsch and Pinker differ on one important philosophical point which is hard to decide. Is the concept of consciousness purely physiological ? Is the human consciousness purely a result of neurons firing in our brain ? If so, he thinks that at some point this can be replaced by silicon chips (or equivalent human made technology) which will result into same level of consciousness as humans. His position on this topic comes from his background in quantum physics.

Pinker however thinks more like a evolutionary biology and indicates that human consciousness or intelligence is extremely diverse. It means different thing for different people and replicating such diversity with machines might be an unsolvable problem. He also seems to think that, there is a possibility that human consciousness might not be just a function of neurons firing in the brain.

Short summary

Overall this discussion is very deep and touches many important aspects of AGI. Both sides agree that we are living in very optimistic times where for the first time in human history AI has shown promise to make major breakthroughs for humanity. Deutsch is more optimistic than Pinker here but both appeared lot more optimistic than average intellectual in this space.