"That vibrations corresponding to all the varieties of sensations and ideas that ever take place in any human, mind may take place in the same brain at the same time, can create no difficulty to any person who considers the capacity of the air itself to transmit different vibrations, without limits, at the same instant of time."
— Priestley, Joseph (1733-1804)
See Hartley’s Theory of the Human Mind, on the Principle of the Association of Ideas; With Essays Relating to the Subject of It. By Joseph Priestley, LL. D. F. R. S. (London: Printed for J. Johnson, No. 72, St. Paul’s Church-Yard, 1775). <Link to ESTC>