RNA

"A healthy, mature human being of normal intelligence may have upwards of 20 million RNA molecules [thought to serve as a ‘filing system’ for memory] in each neuron. . . . An RNA molecule made up of merely 25 links could have any one of a million billion different combinations, . . . In fact, every RNA molecule contains many hundreds of units—not merely 25."

"There is no question, then, that RNA presents a filing system perfectly capable of handling any load of learning and memory which the human being is likely to put upon it—and a billion times more than that quantity, too."