  An implication of Reid's application of his common sense method to first principles is that Reid is not concerned to answer questions of justification that appear pressing to contemporary epistemologists. He is not, for instance, interested in providing a refutation of skepticism about the external world by appeal to first principles. Reid believes he can refute skeptical hypotheses--such as Descartes's hypothesis of an evil demon who makes us believe that the world is the way we take it to be when it is really vastly different--simply by showing that such a hypothesis is no more likely to be true than the common-sensical belief that the world is much the way we perceive it to be. Since the belief in the external world is a dictate of common sense, it is, Reid thinks, as justified as it needs to be when it is shown to be on the same footing as any alternative. Justification, therefore, does not necessarily require providing positive reasons in favor of common-sensical beliefs; common sense beliefs could be adequately justified simply by undermining the force of the reasons in favor of alternatives to common sense. In fact, as we move through this entry, we will witness Reid's repeated deployment of this strategy in the form of burden-of-proof arguments against his major foil, the Way of Ideas. Common sense constrains, rather than dictates, acceptable philosophical positions.