Nagel’s Bat Argument (against Physicalism)
- Physicalism is the thesis that everything that exists is physical.
- Physical facts then, are objective truth (“the kind that can be observed and understood from many points of view and by individuals with different perceptual systems”)
- Even if we knew everything about how the bat’s sonar system works, we would not know what is is like for the bat to perceive using this system.
- ‘What it’s like’: in this case, something is conscious (a bat) if and only if there is something it’s like to be that being (only a bat knows what it is like for a bat to be a bat)
- One, for example, cannot imagine a chair to know what it is like for a chair to be a chair.
- For a state to be conscious is for it to have a subjective character (to seem or feel a certain way to the subject). A conscious experience is a state that is both subjective and qualitative.
- Therefore, complete knowledge of the physical facts about a bat’s perceptual system would not yield knowledge of certain facts about a bat’s experiences
Physicalism leaves out the subjective facts, so it’s a mystery how it could be true (given that qualia and the subjective experience exists).
Related: Frank Jackson’s Knowledge Argument
A famous Taoist story about happiness and knowing what it is like to be a fish
- Zhuangzi and Huizi were strolling on a bridge over the River Hao, when the former observed, “See how the minnows dart between the rocks! Such is the happiness of fishes.”
- “You not being a fish,” said Huizi, “how can you possibly know what makes fish happy?”
- “And you not being I,” said Zhuangzi, “how can you know that I don’t know what makes fish happy?”
- “If I, not being you, cannot know what you know,” replied Huizi, “does it not follow from that very fact that you, not being a fish, cannot know what makes fish happy?”
- “Let us go back,” said Zhuangzi, “to your original question. You asked me how I knew what makes fish happy. The very fact you asked shows that you knew I knew—as I did know, from my own feelings on this bridge.”
Why did Zhuangzi, who wrote it down, show himself to be defeated by his logician friend?