No. 15: Spring 1981
As one goes step-by-step down the ladder of biological complexity, one discovers that flatworms, plants, and even bacteria display purposeful behavior. Bacteria, which are usually regarded as fairly inert when it comes to responding to environmental pressures, actually react in different ways to dozens of different stimuli. This ability at the very least requires sensory equipment, internal clocks, a memory, and a decision-making capability.
If bacterial activity is all preprogrammed (the reductionist view), are not humans also preprogrammed? Human programs are larger and more complex, of course, but still devoid of "thinking." Conversely, if humans really do think; that is, transcend preprogramming (free will, if you wish), then bacteria must also think. The third possibility is that at some step in the ladder of life, "higher" life forms begin to think. There is little evidence that life is split so profoundly between thinkers and non-thinkers.
(Morowitz, Harold J.; "Do Bacteria Think?" Psychology Today, 15:10, February 1981.)
Comment. This ancient controversy about determinism has been revived as:
(1) Simple life forms have been found to be not-so-simple; (2) All life seems unified by a single (or small number of) genetic codes; and (3) "Higher" life forms seem more and more to be just composites of simpler, cooperating biological entities.