 Both doubts appeal to some version of the thesis that the experiences we take as dreams are (at their best) qualitatively similar to those we take as waking – call this the ‘Similarity Thesis’. The Similarity Thesis may be formulated in a variety of strengths. A strong Similarity Thesis might contend that some dreams seem experientially similar to waking, even on hindsight subsequent to waking; a weaker rendering of the thesis might contend merely that dreams seem similar to waking while having them, but not upon waking. Arguably, the sceptical doubt is equally potent on either rendering. Even so, on the most natural reading, the First Meditation passage seems to suggest the stronger view, with its reference to “exactly similar thoughts”: