Minds and Machines

, Volume 16, Issue 2, pp 185–200

Quantity of experience: brain-duplication and degrees of consciousness


DOI: 10.1007/s11023-006-9036-0

Cite this article as:
Bostrom, N. Minds & Machines (2006) 16: 185. doi:10.1007/s11023-006-9036-0


If a brain is duplicated so that there are two brains in identical states, are there then two numerically distinct phenomenal experiences or only one? There are two, I argue, and given computationalism, this has implications for what it is to implement a computation. I then consider what happens when a computation is implemented in a system that either uses unreliable components or possesses varying degrees of parallelism. I show that in some of these cases there can be, in a deep and intriguing sense, a fractional (non-integer) number of qualitatively identical phenomenal experiences. This, in turn, has implications for what lessons one should draw from neural replacement scenarios such as Chalmers’ “Fading Qualia” thought experiment.


ComputationMindConsciousnessImplementationDuplicationFading qualiaChalmersSearleProgramProbabilisticDeterministic

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  1. 1.Faculty of PhilosophyUniversity of OxfordOxfordUK