But you might want to know, and knowing may help you to understand the edifice better.

I’ll presume some basic knowledge of logic. If you’re puzzled about how I use

imperative or deontic logic in earlier chapters, you might look at Sections 8.1 and 8.2 as

you read these chapters. I’ll take an intuitive approach here. Don’t look for technical rules

for well-formed formulas or proofs. A more casual tone fits this present book. I handled

8.1 Imperative Logic

I’ll use these symbols in a standard way:

■ Symbols for not, and, or, if-then, and if-and-only-if: ~, •, , , ■ Parenthesis for grouping: ( ) ■ Quantifiers for all and some: (x), ( x) ■ Modal operators for necessary and possible: ■ Letters for statements, predicates, and relations: A, B, C,… ■ Letters for individual constants: a, b, c,… ■ Letters for individual variables: x, y, z,…

Presume appropriate rules for well-formed formulas and proofs.