A Treatise of Human Nature

Answers

• Q16TRANSCENDENCE

  Would replacing bodily organs with artificial substitutes preserve the identity of the person?

  No. identity through replacement is a fiction. Argues that we ascribe identity to a ship or body whose parts are gradually replaced only because the change is gradual, and that this identity is a fiction of the imagination.

  A change in any considerable part of a body destroys its identity; but it is remarkable, that where the change is produced gradually and insensibly we are less apt to ascribe to it the same effect. The reason can plainly be no other, than that the mind, in following the successive changes of the body, feels an easy passage from the surveying its condition in one moment to the viewing of it in another, and at no particular time perceives any interruption in its actions. From which continued perception, it ascribes a continued existence and identity to the object. But whatever precaution we may use in introducing the changes gradually, and making them proportionable to the whole, it is certain, that where the changes are at last observed to become considerable, we make a scruple of ascribing identity to such different objects. There is, however, another artifice, by which we may induce the imagination to advance a step farther; and that is, by producing a reference of the parts to each other, and a combination to some common end or purpose. A ship, of which a considerable part has been changed by frequent reparations, is still considered as the same; nor does the difference of the materials hinder us from ascribing an identity to it. The common end, in which the parts conspire, is the same under all their variations, and affords an easy transition of the imagination from one situation of the body to another.

  Book I, Part IV, Section 6, 'Of Personal Identity' · Section confirmed on Wikisource and Mattey notes; Gutenberg #4705.