We owe our liberation to chemistry," he went on. "For all perception is but a change in the concentration of hydrogen ions on the surface of the brain cells. Seeing me, you actually experience a disturbance in the sodium-potassium equilibrium across your neuron membranes. So all we have todo is send a few well-chosen molecules down into those cortical mitochondria, activate the right neurohumoral-synaptic transmission effector sites, and your fondest dreams come true. But you knowall this," he concluded, subdued.
Stanisław Lem, The Futurological Congress: From the Memoirs of Ijon Tichy
chemistry, futurology, perception-of-reality, science-fiction