What Didn’t Mary Know?

Loosely defined, the term “qualia” usually refers to the phenomenal aspects of mental experience. Examples from the Stanford Encyclopedia of Philosophy should suffice: “I run my fingers over sandpaper, smell a skunk, feel a sharp pain in my finger, seem to see bright purple, become extremely angry” (Tye, “Qualia”). To undergo any of these experiences, most of us would agree, would entail a very particular feeling. Quite apart from the simple recognition of damage from sandpaper, or the mere identification of a particularly bright shade of purple, there seems to be a qualitative – phenomenal – aspect to each of these mental affairs. Simply put, there is something it is like for you or me to have an experience. Thomas Nagel, Keith Campbell, and Frank Jackson each argue that qualia, in this broad sense, must exist (Nagel, “What Is It Like To Be A Bat?”; Campbell, “A Critique of Central-State Materialism”; Jackson, “Epiphenomenal Qualia”).

However, exactly what “qualia” means to each thinker differs substantially, and the conclusions they draw vary accordingly. Nagel’s analysis allows for qualia to be essentially physical properties of a purely physical realm of the mind and to play a causal role in the physical events of the universe; thus, his analysis of qualia poses no threat to the physicalist doctrine that everything is physical (Stoljar, “Physicalism”). Campbell and Jackson deny that qualia are physical; thus, their analyses of qualia seek to falsify the physicalist premise. This paper contends that Campbell’s and Jackson’s analyses carry no ontological weight, rely on a primary intuition with unclear origins, and lead to highly counterintuitive and worrying consequences. Nagel’s analysis, in contrast, necessitates none of the suspect results that come with Campbell’s and Jackson’s claims. Consequently, we should take Nagel’s account of qualia – which does not show physicalism to be mistaken – to be overwhelmingly preferable.

Nagel approaches the question of qualia by examining what he terms “the subjective character of experience” (323). He clarifies exactly what he means when referring to this subjective element by inviting us to imagine what it would be like to be a different form of life. A bat’s experience when it uses sonar to sense the world, for example, must be completely dissimilar to anything that a human can experience (Nagel 324). Though we may imagine what it would be like “to behave as a bat behaves,” Nagel argues, we cannot imagine what it is like to be this organism (324). Furthermore, it seems to Nagel that physical science as it stands today cannot help us understand what it is like to be something that we are not. A bat’s qualia – Nagel’s what-it-is-likeness – are completely inaccessible to humans through any third-person analysis because their inherently subjective element would necessarily be lost through any objective inquiry (Nagel 323, 326).