Philosophical Studies

, Volume 162, Issue 1, pp 109–117 | Cite as

The Twin Towers riddle

  • Roy Sorensen

A year after the destruction of the Twin Towers, you face south at a location from which the North Tower formerly blocked the view of the South Tower. Can you see the absence of the Twin Towers?

The counterfactual requirement

You see the absence of something only if you occupy a perspective from which you would have seen it. You have adopted an incomplete perspective that would have revealed only the North Tower. Therefore, you are not seeing the absence of the Twin Towers.

Photographers operationalize the counterfactual requirement for seeing absences. They retrieve an old photograph of the object, match the perspective, and take a new photograph. The before and after images are then presented side by side.

This photographic comparison was done after the collapse of the Old Man of the Mountain (the state symbol of New Hampshire). Robert Gallagher took the further step of superimposing the old image on the new image. The result is a composite photograph that sharply delineates the...


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  1. Anscombe, G. E. M. (1971). Causality and determinism. Cambridge University Press.Google Scholar
  2. Armstrong, D. M. (2004). Going through the open door again. In J. Collins et al. (Eds.), Causation and counterfactuals (pp. 445–58) Cambridge: MIT Press.Google Scholar
  3. Butterfill, S. (2009). Seeing causings and hearing gestures. Philosophical Quarterly, 59, 405–428.CrossRefGoogle Scholar
  4. Michotte, A. (1946). The perception of causality (T. Miles, trans.). London: Methuen.Google Scholar
  5. Ramsey, F. (1929). Law and causality. Reprinted In Foundations (1978, pp. 128–51). London: Routledge.Google Scholar
  6. Sartre, J. P. (1969). Being and nothingness (H. E. Barnes, trans.). New York: Washington Square Press.Google Scholar
  7. Schaffer, J. (2004). Causes need not be physically connected to their effects: The case for negative causation. In C. Hitchcock (Ed.), Contemporary debates in philosophy of science (pp. 197–216). Oxford: Blackwell.Google Scholar
  8. Sorensen, R. (2008). Seeing dark things. New York: Oxford University Press.CrossRefGoogle Scholar
  9. Stalnaker, R. (1968). A theory of conditionals. Studies in logical theory, American philosophical quarterly monograph series 2 (pp. 98–112). Oxford: Blackwell.Google Scholar
  10. Strawson, P. F. (1992). Causation and explanation. In Analysis and metaphysics. Oxford: University Press.Google Scholar
  11. White, P., & Milne, E. (1999). Impressions of enforced disintegration and bursting in the visual perception of collision events. Journal of Experimental Psychology: General, 128, 499–516.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  1. 1.Washington UniversitySt. LouisUSA

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