"The Brown Book contains a number of other significant ideas that are developed further in the Philosophical Investigations. Wittgenstein discusses rule following, arguing that there is no rock-bottom justification for the rules we follow and that we need not consciously follow or interpret a rule every time we obey a rule. He discusses the word can and the way that misunderstandings regarding this word give us mistaken notions about the past and future. He also discusses the distinction between seeing and seeing as, arguing that we can see a bunch of squiggles on a page as a face, but we cannot see a fork as a fork, since no alternative presents itself. In other words, when philosophers speak of seeing things “as themselves," in the sense of seeing things in their essence, such statements have no meaning. For example, it would not make sense to speak of seeing someone “as a human being" or “as a person" —there's no difference between that and how we normally see people."