Consciousness is very difficult. In the simplest of words, we can say that consciousness is the awareness (perception) of ourselves and our environment. We might define the perception of two layers of consciousness: the “Deliberate Mind” which reacts immediately to stimuli in our environment, and the “Automatic Mind,” a sort of sub-processor that categorizes information and takes notes for later. But when it comes to the human brain, simple definitions never really satisfy. We’re talking about a system that contains a hundred trillion cells (the human body) which are all unconscious, but somehow come together to become conscious.

We’re trying to define the working of “the Most Complex Object in the Universe,” the human brain, which contains somewhere between 80 and 100 billion neurons. There has long been an argument that it is folly to even try to examine human consciousness since consciousness by its very nature is subjective, but Science requires us to be objective in such an endeavor. Some neuroscientists even believe that our brains fool us, that consciousness doesn’t really exist. “There’s nothing we know about more directly … but at the same time, it’s the most mysterious phenomenon in the universe.”

Defining consciousness
Consciousness is the state or quality of awareness, or, of being aware of an external object or something within oneself. It’s all based in the me-ness and other-ness that is somehow defined as our brains are bombarded by 11 million bits of information per second. Crash Course provides a good overview:

The seat of the self
It’s difficult to pinpoint consciousness to one part of the brain, it probably derives from multiple locations that are essential. For example, we know that damage to a small amount of the brain stem can cause complete body paralysis, but damage to an adjacent area seems to cut off communication with the rest of the brain, and ends consciousness. This points to multiple elements of the brain being required for consciousness. But there is one area of the brain that may be the origin and seat of human consciousness; the prefrontal cortex.

In the book Up From Dragons, John Skoyles and Dorian Sagan explain that the prefrontal cortex makes up from 70 to 80 percent of the frontal cortex in humans, and about 30 percent of gray matter. We also know that only animals later on the evolutionary chain have parallel development of the frontal cortex. Brain scans show that the prefrontal cortex is always at work (even during sleep) except with the possibility a few moments just before sleep, and possibly in deep meditation. And sadly, when know, from results of lobotomy procedures, that destruction of the frontal cortex seems to end consciousness as we know it. Skoyles and Sagan go on to suggest that the prefrontal cortex may serve as an “orchestra master” to bring areas of the brain together into harmony. The brain is capable of working without the prefrontal cortex, but without it, the sense of self seems to disappear. When it comes to the brain, it seems that the prefrontal cortex helps us become greater than the sum of our parts.

The Toba Event
Sometime between 70 to 75 thousand years ago, the Toba volcano in Sumatra, Indonesia erupted. Toba was a super volcano and the eruption was so great that it sent the Earth into a global volcanic winter for 6 to 10 years and probably caused human populations to sharply decreased to 3,000–10,000 surviving individuals. Skoyles and Sagan believe that this created a shift in the human mind, somehow changing us subtly to our current state. It is only after the Toba event that we start seeing hard evidence of human culture. The Blombos Cave Engravings (70,000 BCE), from sub-Saharan African, may be the oldest. It consist of two pieces of ochre rock incised with geometric abstract signs and a series of beads made from Nassarius kraussianus shells.


Blombos Cave Engravings (70,000 BCE), from sub-Saharan African

Professor of Neuroscience, Antonio Damasio framed the possibility this way; there are three Levels of self: proto, core, and autobiographical. Proto and core are shared with other species. It’s the autobiographic self that seems to make humans, it provides us with the ability to build on extended memory, reasoning, imagination, creativity, language which lead to culture: religion, justice, trade, the arts, science, technology, curiosity, understanding of society and culture, and medicine.

It’s just possible that the Toba event was an evolutionary catalyst that took the human mind one step further and created consciousness. The transition wasn’t fast, the “software” took a while to develop – the first known human figures are the Venus sculptures (small ivory carvings of female figures) that first appear in the archaeological record about 38,000-33,000 BCE.

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