Let us approach a much more modest question: not whether we can know the universe or the Milky Way Galaxy or a star or a world. Can we know, ultimately and in detail, a grain of salt? In that grain of salt there are about 1016 sodium and chlorine atoms.
How much can the brain know? There are perhaps 1011 neurons in the brain, the circuit elements and switches that are responsible in their electrical and chemical activity for the functioning of our minds. A typical brain neuron has perhaps a thousand little wires, called dendrites, which connect it with its fellows. If, as seems likely, every bit of information in the brain corresponds to one of these connections, the total number of things knowable by the brain is no more than 1014, one hundred trillion. But this number is only 1 percent of the number of atoms in a speck of salt.
So in this sense the universe is intractable, astonishingly immune to any human attempt at full knowledge. We cannot on this level understand a grain of salt, much less the universe.
For myself, I like a universe that includes much that is unknown and, at the same time, much that is knowable. The ideal universe for us is one very much like the universe we inhabit. And I would guess that this is not really much of a coincidence.
Can We Know the Universe? (1979)
Collected in Boca’s Brain: Reflections on the Romance of Science (1986)
Illustration: Homer Simpson’s Brain
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