For thousands of years, the study of human consciousness was largely the work of philosophers.

Descartes proposed the idea of cogito ergo sum (“I think, therefore I am”), which suggested that the very act of thinking demonstrates the reality of one’s existence and consciousness.

Once psychology was established as a discipline separate from philosophy and biology, the study of the conscious experience became one of the first topics studied by early psychologists.

Neuroscience has also made progress in deciphering how our brains think and perceive our surroundings and define it as the presence of a wakeful arousal state and the awareness and motivation to respond to self and/or environmental events. In the intact brain, arousal is the overall level of responsiveness to environmental stimuli.

Consciousness is the individual awareness of your unique thoughts, memories, feelings, sensations, and environments. Essentially, your consciousness is your awareness of yourself and the world around you.

Consciousness is an essential state in philosophy, spirituality, and religion. All of these require self-awareness, which is impossible without it.

Conscious experiences are constantly shifting and changing.

Consciousness has several biological and social purposes. It allows us to process information, choose our actions, set priorities, learn and adapt to new information, make decisions, 

The two normal states of awareness are consciousness and unconsciousness.

Higher states of consciousness are often associated with spiritual or mystical experiences. It involves an elevated state of awareness where people are able to gain a greater sense of themselves, their role, and the world. 

States of Consciousness

The various states of consciousness include:

• Dreams
• Hallucinations
• Hypnosis
• Meditation
• Sleep
• States induced by psychoactive drugs

Altered levels of consciousness also can occur, which may be caused by medical or mental conditions that impair or change awareness.  Altered types of consciousness include:

• Coma
• Confusion
• Delirium
• Disorientation
• Lethargy
• Stupor

Doctors and healthcare professionals use various assessments to measure and assess levels of consciousness. They use scores on these assessments to guide diagnosis and treatment decisions.

Consciousness has kept philosophers and scientists busy for thousands of years, there is a long way to go in our understanding of it. Researchers continue to explore the different bases of consciousness including the physical, social, cultural, and psychological influences that contribute to our conscious awareness.