Quale

Quale (plural qualia) refers to the subjective, qualitative aspects of conscious experience—the raw feel or sensory character of what it is like to see, hear, taste, or feel something. A single experience for which a quale is invoked is often called the quale of that experience (for example, the redness of red or the pain of a headache). Qualia are typically contrasted with objective properties such as brain states or physical features of objects, because they are argued to be private and directly accessible only through first-person experience.

The term derives from the Latin quale, meaning “of what kind,” and in philosophy of mind it has been used to discuss the intrinsic properties of experiences that seem to resist complete characterization by third-person science. The concept gained prominence in the 20th century within debates about consciousness and the mind–body problem, and it remains a focal point in discussions of what it would take to fully capture experience in physical terms.

Philosophers debate whether qualia exist as non-physical properties, or whether talk of qualia can be reconciled with physicalism. Proponents of the perspective known as property dualism argue that qualitative aspects of experience are real features of consciousness that are not reducible to brain states. Critics, including many physicalists, contend that apparent qualia can be explained by neural processes and that positing non-physical qualities is unnecessary or incoherent. Key thought experiments, such as Mary’s room and the inverted spectrum hypothesis, have shaped this debate by challenging purely physical explanations of experience.

In contemporary work, researchers pursue neural correlates of consciousness to link subjective reports with brain activity, while philosophers continue to assess whether qualia are indispensable to understanding consciousness.

See also: consciousness, philosophy of mind, sensation, perception, Mary’s room, inverted spectrum.