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Artificial Intelligence: A Debate

Is the Brain's Mind a Computer Program?

No. A program merely manipulates symbols, whereas a brain attaches meaning to them

By John R. Searle

Could a Machine Think?

Classical AI is unlikely to yield conscious machines; systems that mimic the brain might

By Patricia Smith Churchland and Paul M. Churchland

Antisense RNA and DNA

Molecules that bind with specific messenger RNA's can selectively turn off genes. Eventually certain diseases may be treated with them; today antisense molecules are valuable research tools...

By Harold M. Weintraub

What Drives Glacial Cycles?

Massive reorganizations of the ocean-atmosphere system, the authors argue, are the key events that link cyclic changes in the earth's orbit to the advance and retreat of ice sheets

By George H. Denton and Wallace S. Broecker

The Handedness of the Universe

From atoms to human beings, nature is asymmetric with respect to chirality, or left- and right-handedness. Clues are beginning to emerge that connect chirality on different levels

By Dilip K. Kondepudi and Roger A. Hegstrom

Stress in the Wild

Studies of free-ranging baboons in an African reserve are helping to explain why human beings can differ in their vulnerability to stress-related diseases

By Robert M. Sapolsky


Two or more atoms-stripped of their outer electrons, trapped by electromagnetic fields and cooled to temperatures near absolute zeroarray themselves in structures that behave like both liquids and solids...

By David J. Wineland and John J. Bollinger

The Cosmic Background Explorer

NASA's cosmological satellite will observe a radiative relic of the big bang. The resulting wealth of data will be scoured for clues to the evolution of structure in the universe

By Philip M. Lubin, Robert F. Silverberg, Samuel Gulkis and Stephan S. Meyer


  • 50 and 100 Years Ago: January 1990

  • Loud and Clear

  • Aftershocks

  • Nanofuture

  • Nit Picker

  • Quasicrystal Clear

  • Bottled Antimatter

  • The Redshift Blues

  • On to the Past

  • A Grave Tale

  • See Spot See Blue

  • Nervous Excitement

  • Sleep of the Guilty

  • Computer Babble

  • Rational Drugs

  • Tensaiji

  • Letters

    Letters to the Editors, January 1990

  • Recommended

    Books, January 1990

  • Profile

    Claude E. Shannon

  • Amateur Scientist

    The Amateur Scientist, January 1990

  • Departments

    The Analytical Economist: Tweaking the Aggregates

  • Computer Recreations, January 1990

  • Essay: Ecological Diplomacy: an Agenda for 1990

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