Subconscious vs. Unconscious: What Are the Key Differences?

When describing someone who has fainted, choosing between subconscious and unconscious is easy—the person who has fainted is unconscious. But in more complex cases, where either term might fit, the distinction isn’t always so obvious.

The use of these terms dates back to Sigmund Freud, who, as noted by Dr. Michael Craig Miller, editor at Harvard Health Publishing, initially used them interchangeably in his early theories on levels of consciousness. These levels are often depicted as an iceberg: the conscious mind (thoughts, feelings, motivations, and everything you're aware of) floats above the water, while the unconscious mind—hidden memories, desires, and other repressed or forbidden things you're unaware of—remains submerged.

Freud eventually discarded the term subconscious in favor of unconscious and redefined his theory of consciousness by introducing the concepts of id, ego, and superego. However, he also identified an intermediary level between the conscious and unconscious minds: the preconscious. Freud believed that although you aren't consciously aware of the contents of your preconscious mind, they are accessible upon reflection.

What some people refer to as the subconscious is, in fact, Freud’s preconscious. Others even consider subconscious and preconscious to be interchangeable. However, if you’re following Freud’s original interpretation, this isn’t accurate. As Dr. Miller points out, professionals in psychology, neurology, psychiatry, and related fields generally avoid using the term subconscious in scientific discussions altogether.

That being said, Freud didn’t coin the terms subconscious or unconscious, and they’re not limited to the realm of science. In everyday conversation, calling an emotion “unconscious” might suggest it’s buried deeper than a subconscious one. But as Grammarist clarifies, you can generally use either word to describe something you're unaware of.