 This reflection that is essential to any thought, however, does not involve a second order perception. Each thought, according to Arnauld, has reflection built into it—a representation of the subject of thought is an essential part of the content of each thought. This is what he calls “simple” or “virtual reflection” to distinguish it from the sort of reflection that is a result of the subject focusing her attention on some other thought, which does require a second-order thought taking the lower-order thought as its object. (See Nadler 1989, 118–22 for discussion of this.)