Publisher Summary A mark is a more or less connected inscription. Among the marks are the Latin letters, the Greek letters, and the ten Arabic numerals. Underlining is thought of as touching any inscription immediately above it. If one nonitalicized Latin letter is printed close beside another as in a word then they are thought of as touching. In this connection, the ten Arabic numerals are thought of as nonitalicized Latin letters. c is a symbol if and only if c is a mark that is not a quotation mark. An expression is a linear array of symbols. Quotation marks play a central role in the chapter. The possibility of contradiction would arise primarily from the inclusion of quotation marks among the symbols rather than imagined technical defects. To discuss an object, a name must be employed for it and not the object itself. A name for an expression is formed by placing the expression between single quotation marks.