““When once we quit the basis of sensation, all is in the wind. To talk of immaterial existences is to talk of nothings . To say that the human soul, angels, god, are immaterial, is to say they are nothings , or that there is no god, no angels, no soul. I cannot reason otherwise: but I believe I am supported in my creed of materialism by Locke , Tracy , and Stewart . { Letter to John Adams , from Monticello, 15 August 1820 }””