Lecture 4.2: What It Is Like to Be a Bat and the Nature of Subjectivity

Historical Context: In a famous article written in the 1970s, philosopher Thomas Nagel posed the fundamental question: "What's it like to be a bat?"
The Problem of Other Minds: Nagel suggests that humans can generally form a reasonable idea of what it is like to be another human being. We can even approximate an understanding of the experience of a dog.
The Specificity of the Bat: The bat presents a unique challenge to human understanding due to its sensory mechanisms.
- Perceptions: Bats clearly possess perceptions; they navigate their environments successfully without colliding with objects.
- Echolocation: Unlike humans, who primarily navigate visually, bats perceive their world through echolocation.
- The Failure of Imagination: When a human attempts to imagine being a bat, they almost inevitably rely on visual imagery. However, since bats navigate via echolocation rather than sight, this visual imagination fundamentally fails to capture the bat's reality. Echolocation "doesn't look" like anything in the visual sense.
Qualia: The lecture introduces the concept of "bat qualia," referring to the internal, subjective quality of the bat's sensory experiences.

Standard Definition: Since Nagel's article, the phrase "what it's like" has become the standard philosophical shorthand for discussing phenomenally conscious states.
Inside vs. Outside Perspectives:
- Subjective Experience: Understanding "what it's like" for someone else is akin to "putting yourself in someone else's shoes."
- Reliving vs. Analyzing: This process is not about deducing what another person is thinking, what they believe, or what they desire from an external perspective. Instead, it is about attempting to "relive" or experience their reality from the "inside."
The Problem for Consciousness Theories: The inability to access the internal experience of the bat poses a significant challenge for certain scientific or reductionist theories of consciousness.

Single Point of View: Consciousness is subjective because conscious states are only accessible from a single, private point of view.
Internal Accessibility: A person knows what they are thinking from the "inside." An observer can never know those thoughts from the "outside" in the same way the subject knows them from the inside.
Defining Subjectivity: The speaker clarifies two distinct meanings of the word "subjective":
- Common Usage (Opinion): Often, subjective means "in the eye of the beholder," referring to matters of taste, such as whether a movie or a book is good.
- Philosophical Usage (Perspective): In the context of consciousness, subjectivity does not mean there are no facts. Rather, it means that the facts are the observer's perspective. It is not just "in the eye of the beholder"; it is the "eye of the beholder."

Empiricism: John Locke's position is rooted in empiricism—the claim that knowledge of a quality cannot exist until that quality has been experienced.
Locke's Hypothetical Scenario:
- If a child were raised in a place where they never saw anything but black and white until they reached adulthood, that person would have no idea what "scarlet" or "green" is.
- Similarly, a person who has never tasted an oyster or a pineapple cannot have an idea of those specific "relishes" (flavors).
Essential Linkage: Locke argues that the experience and the quality are inseparable.
- The smell of lavender consists entirely in the experience of smelling it.
- There are no smells independent of smellings, no sounds independent of hearings, and no sights independent of seeing.
Distinction from Idealism: Locke is not an idealist (the belief that physical objects do not exist unless perceived). He believes objects exist, but the sensory qualities (seeing, hearing, smelling) exist only within the act of the subject perceiving them.

Conceptual Challenges: These ideas regarding the subjective and phenomenal nature of experience create difficulties for various accounts of the mind.
Upcoming Topics: The discussion will move toward the distinction between "access consciousness" and "phenomenal consciousness" to further clarify why the latter is so difficult to define and discuss.