In 1943 the Nobel Prize winning physicist, Erwin Schrodinger, gave some lectures in Dublin where he was living in exile. He converted them into a short book, What Is Life?, the following year. He coined the term aperiodic crystal to describe the then unknown macromolecule which he hypothesised must carry genetic material. Watson and Crick later acknowledged the stimulus provided by the physicist to their work on DNA. Schrodinger also discussed the thermodynamic issues raised by living things, and how they carried order into the next generation without its dissipation. In the final and most speculative part of the book he considered consciousness and free will. He recorded his admiration for the Eastern religious tradition as recorded in the Upanishads. He felt that despite our experience of individual identity, the deeper truth was of one undivided unity of mind and spirit.
Are we now better placed to identify what are the essential characteristics of life? The modern temper resists essentialism, in effect Platonism or the priority of Platonic ideas over empirical data. Wittgenstein’s family resemblances seem less ambitious and perhaps a more productive way of enquiring. It is not difficult to find generalisations which distinguish inanimate matter from plant and animal life. As regards plant and animal life, mobility or its lack, a nervous system or its absence, asexual reproduction or its absence, are points of divergence. There are exceptions and borderline cases, most strikingly in protozoa. The presence of intentional behaviour is one of the most characteristic features of animal life. Though plants grow towards light and their roots towards water, these tropisms seem to be without experiential content. Some intentional behaviours seem innate and elicited as soon as a suitable stimulus is encountered by the organism for the first time. Is such a response inflexible or invariable, or does the organism sometimes offer an unobtrusive assent or refusal? I don’t think the latter possibility should be excluded, in the interests of insisting on a difference between mechanism and organism. Learned behaviour is of course more complex and unpredictable.
The force of Thomas Nagel’s phrase ‘ There is something it is like to be a bat’ is that animals, even lowly ones, encounter the world with an intentional stance, and this gives them a sense of identity through time. At its simplest disposition is embodied memory unless it is inflexibly determined by the genes. Memory, perceiving the present environment and judging how the future might unfold are all intrinsic to the decision making of purposive behaviour. But purposive behaviour need not have a definite purpose in view. It may be exploratory, playful, opportunistic. Above all it always moves the organism into the boundless and uncertain open. It seeks to improve the way the organism feels about itself. And there is something holistic about it. This wonderful stanza, with its homely simile in the last two lines, from Octets by Osip Mandelstam, expresses something of that mystery.
Vestigial presence of a sixth sense, lizard's sincipital third eye, the monasteries of snails and bivalves, rustle of shimmering cilia. Impossible to grasp what's very near, look into it minutely or see it whole - as if a letter were thrust into one's hand and one had to give an answer straightaway.