 In support of the positive resemblance between PQs and ideas of them, Locke appeals to practical action: it is by being moved from A to B that a body causes the idea of its motion from A to B. so the idea represents motion “as it really is” in the body (E 2.8.18); “A Circle or Square are the same whether in Idea or Existence.” (E 2.8.18) Quick as this argument is, it is taken to show that motion and figure “are really in bodies whether we take notice of them or no.” (E 2.8.18) The following sections 19 through 21 propose thought experiments regarding the color of porphyry in the presence and absence of light, the taste of an almond before and after a pounding, and a bowl of water in which one person has placed both hands one of which has been in ice water and the other in hot water. Curley (1972) decisively argues that none of this is meant to show that appearances of SQs—unlike PQs—are perceiver relative unreliable bases on which to judge the properties of things we perceive. But scholars have had difficulty seeing what the examples are intended to show: whether to substantiate the resemblance thesis, the corpuscular theory, or the reality of qualities and non reality of powers. For different views, see, e.g., Alexander (1985: 124–29), Atherton (1992), Lowe (2005: 51–2), Rickless (2014: 88–93), McCann (2011: 175–6). Robert Wilson (2004: 204–06); on the color of porphyry, Stuart (2003) and Jacovides (2007b: 641–2).