History of Consciousness Study

The definition of consciousness proposed by English philosopher John
Locke (1632-1704)—“the perception of what passes in a man’s own mind”—
has been that most generally accepted as a starting point in understanding
the concept. Most of the philosophical discussions of consciousness, however,
arose from the mind-body issues posed by the French philosopher and
mathematician René Descartes (1596-1650). Descartes raised the essential
questions that, until recently, dominated consciousness studies. He asked whether the mind, or consciousness, is independent of matter, and whether
consciousness is extended (physical) or unextended (nonphysical). He also
inquired whether consciousness is determinative or determined. English
philosophers such as Locke tended to reduce consciousness to physical sensations
and the information they provide. European philosophers such as
Gottfried Wilhelm Leibniz (1646-1716) and Immanuel Kant (1724-1804),
however, argued that consciousness had a more active role in perception.
The nineteenth century German educator Johann Friedrich Herbart
(1776-1841) had the greatest influence on thinking about consciousness.
His ideas on states of consciousness and unconsciousness influenced the
German psychologist and physiologist Gustav Theodor Fechner (1801-
1887) as well as the ideas of Sigmund Freud (1856-1939) on the nature of
the unconscious.

The concept of consciousness has undergone significant changes since
the nineteenth century, and the study of consciousness has undergone serious
challenge as being unscientific or irrelevant to the real work of psychology.
Nineteenth century scholars had conflicting opinions about consciousness.

It was either a mental stuff different from everyday material or a
physical attribute like sensation. Sensation, along with movement, separates
humans and other animals from nonsensate and immobile lower forms of
life. Scholars viewed consciousness as different from unconsciousness, such
as occurred in sleep or under anesthesia. Whatever the theory, these scholars
generally employed the same method, that of introspection.