| Descartes (1596-1650) | mind | body | matter |
John Locke (1632-1704) | mind | sensory [secondary quality] | matter [primary quality] | |
Kant (1724-1804) | brain | cognition | thing-in-itself | |
statistics (scientific theory) | trial person [sample] | trial [?] | population [parameter] | |
QL (scientific theory) | observer [measured value] | measuring instrument [observable] | System [state] |