To construct the states of nature, W, start with an exhaustive set of 
propositions of states L= {p1,...,pk}

let xi in {p1, !p1}

Consider C = the set of all x1 /\ ... /\ xk

Weed out all inconsistent propositions.  The remainder is the states of 
nature, W.

Note that w1 \/ .. \/ wn = true.