The phrase “sixth sense” entered wide usage in English through the writing of Helena Blavatsky, the founder of Theosophy. Blavatsky appropriated concepts from Indian traditions such as yoga and Buddhism and crafted them into an occult movement. Distorted ideas about karma and reincarnation stem from Blavatsky’s popularity, and the “sixth sense” suffered a similar fate.

Scientists who study perception and sensation identify far more then five senses in human anatomy. In addition to those listed above, humans have a sense of balance, a kinesthetic sense, and several others. Theosophy’s “sixth sense” must be understood as a framework for sensation and perception, appropriated from Indian philosophy to enhance Blavatsky’s mystique.

Buddhist philosophers recognized six senses: sight, hearing, taste, touch, small, and mind. The last sense refers to the awareness of thoughts, memories, imagination, and other cognitive phenomena. Metaphysical arguments in Buddhist sutras describe experience as requiring a sensory organ, sensory stimulation, and sensory consciousness. Since one experiences thoughts and memories, one must also have a sense that enables the experience. The “sixth sense” here is a straightforward way of talking about mental experiences like dreams or imagination.

In the Buddhist framework, the six senses are part of a naturalistic phenomenology that rejects distinguishing between “internal” and “external” phenomena. The European philosophical tradition often frames mental phenomena against mind-body dualism, a view that “physical” and “mental” phenomena consist of fundamentally different substances. Buddhist phenomenologists instead frame all objects of experience as sharing the same essential substance. A subject experiences sight, sound, and thought through different sense modalities, but the Buddhist framework does not infer differing substances from differing modalities.

Differentiating experiences as “internal” or “external” is not coherent because the subject experiences all sense modalities as a uniform flow of sensory stimulation. As a consequence Buddhist metaphysics rejects mind body dualism. The subject knows themself a continuity of sensory organs, sensory consciousness, and sensory stimuli, a fundamentally non-dual metaphysics. By framing “the sixth sense” as extrasensory perception, Blavatsky reintroduces dualist metaphysics to an account of sensation that should reinforce non-dualism.