In his book Deep, James Nestor describes how he became passionate about the oceans, marine life, and our connections to the water as humans. When he began his research of free diving and started to study marine mammals and our resemblance to marine life, he was surprised. Nestor wrote, “We’re born of the ocean. Each of us begins life floating in amniotic fluid that has almost the same makeup as ocean water.” Nestor begins with human life as a fetus comparing human embryonic development to that of fish. “Our earliest characteristics are fishlike. The month-old embryo grows fins first, not feet.” As he continues, Nestor spends a lot of time discussing the similarities in our development to that of marine mammals and marine life to show that somewhere in our human past we began life in the ocean, and evolved from life in the ocean. His position is strengthened when he compares the chemical composition of human blood to sea water, noting the similarities of our blood PH, and he continues the comparison by examining what many call “The Master Switch of Life”, or the mammalian dive reflex.
Nestor first encountered the mammalian dive reflex when he watched a group of people exploit our amphibious reflexes to dive to depths of nearly 300 feet in a free diving competition in the Mediterranean. He was amazed by the capacities of the human body to adjust in water and accomplish things that seemed impossible below the surface, but he was abhorred by the competition aspect of free diving that pushed people beyond their limits and often left competitors bloody and semiconscious.
Throughout his book Nestor continually refers back to the idea of human closeness to the ocean. By describing our developmental similarities and evolutional ties to marine life in the quote above, he sets a foundation for the rest of his book that shows how natural free diving and unassisted human exploration of the ocean can be. He rejects the competition aspect of free diving because it leaves the competitor at a point where they no longer focus on the ocean and their connection to it, but rather push through the water ignoring all senses until they reach a desired depth. For Nestor, understanding our connection to the ocean means understanding human beings and life in a more intimate way. Seeing ourselves as evolutionarily bound to the ocean allows him to paint a new picture of the oceans importance for us, and became truly captivating for Nestor who had previously never given the ocean a second thought.