Defining the Undefinable: The Living Cell

December 19, 2001 | Source: New York Times

In the controversy of extracting stem cells from human embryos for possible use in the treatment of diseases, researchers must weigh not only the question of when human life begins, but what being alive really means.
Are the following “alive” or not?

  • Monkey eggs that can be chemically treated and modified to the point where they begin behaving enough like embryos to generate stem cells without the addition of sperm.
  • RNA molecules that replicate in a test tube.
  • The economy and the Internet, which like ants, are super organisms, with the individual functions widely distributed yet intimately connected, mutually responsive, dynamic and ever-changing.
  • Artificial life — simple computer instructions that create forms that aggregate into diverse digital “ecosystems.”
  • A computer for which a judge cannot distinguish between the answers given by a computer and those from a person (the Turing test).
  • The virus, which has no metabolism or self- maintenance, yet forces its host cells to devote most of their metabolic energy to the production of new viruses.
  • The prion, an infectious protein that lacks a nucleic blueprint but multiplies in the brains of its hosts.

    Dr. Bedau of Reed College argues that the key to life is “supple adaptation,” the capacity of populations or groups to respond to changing circumstances by continually creating new adaptations.

    In this vein, some experts say, the current stem cell debate, by focusing on human embryos in the laboratory and divorced from their ordinary biological and evolutionary context, ignores the connectivity of the human race — specifically, the relationship between the mother and her gestating fetus. The quickening (first movement) could define the beginning of life, says Dr. Barbara Katz Rothman, a bioethicist and professor of sociology at the City University of New York.