Self Comes to Mind

that conscious and nonconscious processes coexist but rather that nonconscious processes that are relevant to maintaining life can exist without their conscious partners.
    As far as mind and consciousness are concerned, evolution has brought us different sorts of brains. There is the sort of brain that produces behavior but does not appear to have mind or consciousness; an example is the nervous system of Aplysia californica , the marine snail that became popular in the laboratory of the neurobiologist Eric Kandel. Another sort produces the whole range of phenomena—behavior, mind, and consciousness—human brains are the prime example, of course. And a third sort of brain clearly produces behavior, is likely to produce a mind, but whether it generates consciousness in the sense discussed here is not so clear. That is the case of insects.
    But the surprises do not end with the notion that in the absence of mind and consciousness brains can produce respectable behaviors. It turns out that living creatures without any brain at all, down to single cells, exhibit seemingly intelligent and purposeful behavior as well. And that too is an underappreciated fact.
    There is no doubt that we can gain useful insights into how human brains produce conscious minds by understanding the simpler brains that produce neither mind nor consciousness. As we engage in that retrospective survey, however, it becomes apparent that in order to explain the rise of such long-ago brains we need to go even deeper into the past, further back into the world of simple life-forms, devoid of both minds and brains, those life-forms that are unconscious, unminded, and un brained. In fact, if we are to find out the rhymes and reasons behind conscious brains, we need to get closer to the beginnings of life. And here once again we come to notions that not only are surprising but undermine commonly held assumptions about the contributions of brains, minds, and consciousness to the management of life.
Natural Will
     
    We need a fable again. Once upon a time life came about in the lengthy history of evolution. This was 3.8 billions of years ago, when the ancestor of all future organisms made its first appearance. Some two billion years later, when successful colonies of individual bacteria must have seemed to own the earth, it was the turn of single cells equipped with a nucleus. Bacteria were single living organisms too, but their DNA had not been collected in a nucleus. Single cells with a nucleus were a notch up. These life-forms were known technically as eukaryotic cells, which belong to a large group of organisms, the Protozoa. Back in the morning of life, such cells were some of the first truly independent organisms. Each of them could survive individually without symbiotic partnerships. Such simple single organisms are still with us today. The lively amoeba is a good example, and so is the wonderful paramecium. 1
    A single cell has a body frame (a cytoskeleton), inside which there is a nucleus (the command center that houses the cell’s DNA) and a cytoplasm (where the transformation of fuel into energy takes place under the control of organelles such as mitochondria). Bodies are demarcated by skins, and the cell does have one, a boundary between its interior and the exterior world. It is called the cell membrane.
    In many respects a single cell is a preview of what a single organism such as ours would come to be. One can see it as a sort of cartooned abstraction of what we are. The cytoskeleton is the scaffolding frame of the body proper, just as the bone skeleton is in all of us. The cytoplasm corresponds to the interior of the body proper with all its organs. The nucleus is the equivalent of the brain. The cell membrane is the equivalent of the skin. Some of these cells even have the equivalent of limbs, cilia, whose concerted movements allow them to swim.
    The separate components of a eukaryotic cell came together by way of cooperation among simpler individual creatures, namely, bacteria that gave up their independent status to be a part of a convenient new aggregate. A certain kind of bacterium gave rise to mitochondria; another kind, such as spirochetes, helped with the cytoskeleton and with cilia, for those that liked to swim, and so forth. 2 The marvel is that each of our own multicellular organisms is put together according to this same basic strategy, by aggregating billions of cells so as to constitute tissues, pulling together different