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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 kinds of tissue so as to constitute organs, and connecting different organs so as to form systems. Examples of tissues include the epithelia of skin, mucosal linings and endocrine glands, the muscular tissue, the nervous or neural tissue, and the connective tissue that binds them all in place. Examples of organs are obvious, from hearts and guts to the brain. Examples of systems include the ensemble formed by the heart, blood, and blood vessels (the circulatory system), the immune system, and the nervous system. As a result of this cooperative arrangement, our organisms are highly differentiated combinations of trillions of cells of varied kinds, including, of course, neurons, the most distinctive constituents of the brain. More about neurons and brains in a minute.
    The main difference between the cells found in multicellular (or metazoan) organisms and the cells of unicellular organisms is that while single cells must fend for themselves, the cells that constitute multicellular organisms live