Grammar is a science dealing with the formulation of the proper methods of verbal expression and communication, i.e., the methods of organizing words (concepts) into sentences. Grammar pertains to the actions of consciousness, and involves a number of special concepts — such as conjunctions, which are concepts denoting relationships among thoughts (“and,” “but,” “or,” etc.). These concepts are formed by retaining the distinguishing characteristics of the relationship and omitting the particular thoughts involved.
Adverbs are concepts of the characteristics of motion (or action); they are formed by specifying a characteristic and omitting the measurements of the motion and of the entities involved — e.g., “rapidly,” which may be applied to “walking” or “swimming” or “speaking,” etc., with the measurement of what is “rapid” left open and depending, in any given case, on the type of motion involved.
Prepositions are concepts of relationships, predominantly of spatial or temporal relationships, among existents; they are formed by specifying the relationship and omitting the measurements of the existents and of the space or time involved — e.g., “on,” “in,” “above,” “after,” etc.
Adjectives are concepts of attributes or of characteristics. Pronouns belong to the category of concepts of entities. Conjunctions are concepts of relationships among thoughts, and belong to the category of concepts of consciousness.
The purpose of conjunctions is verbal economy: they serve to integrate and/or condense the content of certain thoughts.
For instance, the word “and” serves to integrate a number of facts into one thought. If one says: “Smith, Jones and Brown are walking,” the “and” indicates that the observation “are walking” applies to the three individuals named. Is there an object in reality corresponding to the word “and”? No. Is there a fact in reality corresponding to the word “and”? Yes. The fact is that three men are walking — and that the word “and” integrates into one thought a fact which otherwise would have to be expressed by: “Smith is walking. Jones is walking. Brown is walking.”
The word “but” serves to indicate an exception to or a contradiction of the possible implications of a given thought. If one says: “She is beautiful, but dumb,” the “but” serves to condense the following thoughts: “This girl is beautiful. Beauty is a positive attribute, a value. Before you conclude that this girl is valuable, you must consider also her negative attribute: she is dumb.” If one says: “I work every day, but not on Sunday,” the “but” indicates an exception and condenses the following: “I work on Monday. I work on Tuesday. (And so on, four more times.) My activity on Sunday is different: I do not work on Sunday.”
(These examples are for the benefit of those victims of modern philosophy who are taught by Linguistic Analysis that there is no way to derive conjunctions from experience, i.e., from the facts of reality.)