 In addition to the debate over what consciousness is, and what Locke means when he says that the identity of any person consists in the identity of consciousness, there is ongoing debate about what Locke’s stance is when it comes to what can give rise to consciousness. That is, there is ongoing discussion of what Locke means when he says that God could have superadded thinking to formerly inert systems of matter, and what Locke’s actual position is on the substantial nature of finite thinkers. There are those who take Locke to be truly agnostic. Those who take this line of interpretation remind readers of Locke’s stated aims at the start of the Essay (as quoted earlier), and the epistemic modesty that Locke maintains throughout the text. But, there are others who think that Locke overstates the probability that souls are immaterial substances, so as not to ruffle the feathers of Stillingfleet and other religious authorities. Some in the latter group think that Locke leans toward materialism. This raises questions about how far Anthony Collins (discussed below) departs from the Lockean picture, or the degree to which Locke anticipates later materialist pictures of  persons.[7]  At the very least, it can be said that Locke challenges the importance that many philosophers place on the immaterial soul to personhood and personal  identity.[8]  As might be expected, this was met with mixed reviews.