 The first, and in many ways most important of these Cartesian teachings was the method of universal doubt. We should retain beliefs only if they are absolutely certain and we are unable to doubt them. The test of this certainty, as Peirce next points out, lies in whether the individual consciousness is satisfied. Importantly, this self-examination includes reflection on hypothetical possibilities: we cannot trust our perceptual beliefs, for example, because we cannot rule out that they might be produced by a dream, or an evil demon. (See Hookway 2012, chapters 2,3.) The initial pragmatist response to this is that it is a strategy that in practice we cannot carry out effectively, and there is no reason to adopt it anyway. Peirce claims that any attempt to adopt the method of doubt will be an exercise in self-deception because we possess a variety of certainties which it does not occur to us can be questioned. So what is produced will not be ‘real doubt’; these beliefs will lurk in the background, influencing our reflection. Peirce urges us not to ‘pretend to doubt in philosophy what we do not doubt in our hearts’ (EP1: 29). 