Abstract

By an argument form I shall mean a schema consisting of a string of symbols that are place-­‐holders for either logical terms or non-­‐logical (descriptive/content) terms: substituting terms of the appropriate kind for the symbols yields an argument. A substitution instance of an argument form is an argument that arises as a result of such a substitution. By a valid argument I shall mean an argument such that it is impossible for the premises to be true and the conclusion false. Thus, an invalid argument is an argument such that it is possible for the premises to be true and the conclusion false