Hartley, David (1705–1757)

David Hartley’s Observations on Man, His Frame, His Duty, and His Expectations (1749) offers an inclusive study of human beings, one that brings together neuro-physiology, cognitive and moral psychology, and theology. According to Hartley, the ‘frame’ of body and brain grounds consciousness, so that mind is not something separate from body. Experiences of happiness and suffering combine to shape a person’s evolving sense of self, and this self may grow into awareness of our duty to act always out of love. Expectations of one’s place in the vastness of time help bring this growth about, for these put into perspective the pleasures and pains of the present moment.

‘Association’ is the central principle unifying Hartley’s Observations on Man At the end of the first volume, Hartley makes a bold statement: if an organism ‘could be endued with the most simple kinds of sensation, [it] might also arrive at all that intelligence of which the human mind is possessed’ (17949, vol. 1: Conclusion). Just as association can account for the ‘mind’ of a jellyfish, so also can the theory account for the forms of intelligence that go into living complete human lives. Association first names the physiological processes that generate ideas, and then the psychological processes by which perceptions, emotions, and thoughts fuse or break apart. These processes involve mastering the skilled (‘decomplex’) actions that fill our daily lives, as well as the acts by which the self forms and transforms, as we grow in sympathy, ‘theopathy’ and the moral sense.