  Now this may seem impossible; how can one and the same thing occur more than once without there being two tokens of it? Simons (1982) concludes that it can't. Wetzel (1993) argues that it is useful to distinguish objects from occurrences of them. For example, in the sequence of numbers &lt;0,1,0,1&gt; the very same number, the number one, occurs twice, yet its first occurrence is distinct from its second. The notion of an occurrence of x in y involves not only x and y, but also how x is situated in y. Even a concrete object can occur more than once in a sequence—the same person occurs twice in the sequence of New Jersey million dollar lottery winners, remarkably enough. If we think of an expression as a sequence, then the air of mystery over how the same identical thing can occur twice vanishes. Does this mean that, in addition to word types and word tokens, word occurrences must also be recognized? Not necessarily; we can unpack the notion of an occurrence using “occurs in” if we have the notion of a sequence available; see Wetzel 1993 for details.