Rene Descartes 1596-1650 Rene Descartes 1596-1650

4. The Evil Deceiver:Can we be sure that such beliefs are true, that, for instance, 1 + 1 = 2? Is therean alternative explanation for why we believe this, other than it is true?There could be an extremely powerful deceiver who brings about that wheneveryou think 1+1=2, you are wrong. Can you be certain that there is no suchdeceiver?Another way of thinking about this is simply to suppose that your brain waswired up incorrectly, so that whenever you think of a false thought, such as 1 +1 = 3, you have feeling of certainty that it is true, and whenever you think atrue thought, 1 + 1 = 2, you have a feeling of certainty that it is false.Now, how do you know that this is not the case? Could an evil deceiver havescrambled your brains, so that you are constantly confused? Can you be certainthat this has not happened to you?47