• logical possibility;
  • philosophical methodology;
  • physical possibility;
  • physical scale effects;
  • thought experiments

Abstract: The scales across which physical properties exist are vast and subtle in their effects on particular systems placed locally on such scales. For example, human experiential access is restricted only to partial segments of the mass density, size, and temperature scales of the universe. I argue that philosophers must learn to appreciate better the effects of physical scales. Specifically, thought experiments in philosophy should be more sensitive to physical scale effects, because the conclusion of a thought experiment may be undermined by unintentionally ignored scale effects, and the changes required to obtain the foreground state of affairs in a thought experiment might require unacknowledged scale-spanning changes to the contextual background. I discuss four philosophical thought experiments: Putnam's Twin Earth and Brain in a Vat, Searle's Chinese Room, and Chalmers's Zombies Without Qualia. I close by briefly defending the greater interest and importance of physical possibility over logical possibility.