From Harold Garfinkel, Studies in Ethnomethodology. Englewood Cliffs, NJ: Prentice- Hall, 1967, pp. 38-44, 75.
Various considerations dictate that common understandings cannot possibly consist of a measured amount of shared agreement among persons on certain topics. Even if the topics are limited in number and scope and every practical difficulty of assessment is forgiven, the notion that we are dealing with an amount of shared agreement remains essentially incorrect. This may be demonstrated as follows.
Students were asked to report common conversations by writing on the left side of a sheet what the parties actually said and on the right side what they and their partners understood that they were talking about. A student reported the following colloquy between himself and his wife.
|HUSBAND:||Dana succeeded in putting a penny in a parking meter today without being picked up.||This afternoon as I was bringing Dana, our four-year-old son, home from the nursery school, he succeeded in reaching high enough to put a penny in a parking meter when we parked in a meter parking zone, whereas before he has always had to be picked up to|
|WIFE:||Did you take him to the record store?||Since he put a penny in a meter that means that you stopped while he was with you. I know that you stopped at the record store either on the way to get him or on the way back. Was it on the way back, so that he was with you or did you stop there on the|
|HUSBAND:||No, to the shoe repair shop.||No, I stopped at the record store on the way to get him and stopped at the shoe repair shop on the way home when he was with me.|
|WIFE:||What for?||I know of one reason why you might have stopped at the shoe repair shop. Why did you in fact?|
|HUSBAND:||I got some new shoe laces for my shoes.||As you will remember I broke a shoe lace on one of my brown oxfords the other day so I stopped to get some new laces.|
|WIFE:||Your loafers need new heels badly.||Something else you could have gotten that I was thinking of. You could have taken in your black loafers which need heels badly. You'd better get them taken care of pretty soon.|
An examination of the colloquy reveals the following. (a) There were many matters that the partners understood they were talking about that they did not mention. (b) Many matters that the partners understood were understood on the basis not only of what was actually said but what was left unspoken. Many matters were understood through a process of attending to the temporal series of utterances as documentary evidences of a developing conversation rather than as a string of terms. (d) Matters that the two understood in common were understood only in and through a course of understanding work that consisted of treating an actual linguistic event as "the document of," as "pointing to," as standing on behalf of an underlying pattern of matters that each already supposed to be the matters that the person, by his speaking, could be telling the other about. The underlying pattern was not only derived from a course of individual documentary evidences but the documentary evidences in their turn were interpreted on the basis of "what was known" and anticipatorily knowable about the underlying patterns.  Each was used to elaborate the other. (e) In attending to the utterances as events-in-the-conversation each party made references to the biography and prospects of the present interaction which each used and attributed to the other as a common scheme of interpretation and expression. (f) Each waited for something more to be said in order to hear what had previously been talked about, and each seemed willing to wait.
Common understandings would consist of a measured amount of shared agreement if the common understandings consisted of events coordinated with the successive positions of the hands of the clock. i.e., of events in standard time. The foregoing results, because they deal with the exchanges of the colloquy as events-in-a-conversation, urge that one more time parameter, at least, is required: the role of time as it is constitutive of "the matter talked about" as a developing and developed event over the course of action that produced it, as both the process and product were known from within this development by both parties, each for himself as well as on behalf of the other.
The colloquy reveals additional features. (1) Many of its expressions are such that their sense cannot be decided by an auditor unless he knows or assumes something about the biography and the purposes of the speaker, the circumstances of the utterance the previous course of the conversation, or the particular relationship of actual or potential interaction that exists between user and auditor. The expressions do not have a sense that remains identical through the changing occasions of their use. (2) The events that were talked about were specifically vague. Not only do they not frame a clearly restricted set of possible determinations but the depicted events include as their essentially intended and sanctioned features an accompanying "fringe" of determinations that are open with respect to internal relationships, relationships to other events, and relationships to retrospective and prospective possibilities. (3) For the sensible character of an expression, upon its occurrence each of the conversationalists as auditor of his own as well as the other's productions had to assume as of any present accomplished point in the exchange that by waiting for what he or the other person might have said at a later time the present significance of what had already been said would have been clarified. Thus many expressions had the property of being progressively realized and realizable through the further course of the conversation. (4) It hardly needs to be pointed out that the sense of the expressions depended upon where the expression occurred in serial order, the expressive character of the terms that comprised it, and the importance to the conversationalists of the events depicted.
These properties of common understandings stand in contrast to the features they would have if we disregarded their temporally constituted character and treated them instead as precoded entries on a memory drum, to be consulted as a definite set of alternative meanings from among which one was to select, under predecided conditions that specified in which of some set of alternative ways one was to understand the situation upon the occasion that the necessity for a decision arose. The latter properties are those of strict rational discourse as these are idealized in the rules that define an adequate logical proof.
For the purposes of conducting their everyday affairs persons refuse to permit each other to understand "what they are really talking about" in this way. The anticipation that persons will understand, the occasionality of expressions, the specific vagueness of references, the retrospective-prospective sense of a present occurrence, waiting for something later in order to see what was meant before, are sanctioned properties of common discourse. They furnish a background of seen but unnoticed features of common discourse whereby actual utterances are recognized as events of common, reasonable, understandable, plain talk. Persons require these properties of discourse as conditions under which they are themselves entitled and entitle others to claim that they know what they are talking about, and that what they are saying is understandable and ought to be understood. In short, their seen but unnoticed presence is used to entitle persons to conduct their common conversational affairs without interference. Departures from such usages call forth immediate attempts to restore a right state of affairs.
The sanctioned character of these properties is demonstrable as follows. Students were instructed to engage an acquaintance or a friend in an ordinary conversation and, without indicating that what the experimenter was asking was in any way unusual, to insist that the person clarify the sense of his commonplace remarks. Twenty-three students reported twenty-five instances of such encounters. The following are typical excerpts from their accounts.
The subject was telling the experimenter, a member of the subject's car pool, about having had a flat tire while going to work the previous day.
(S) I had a flat tire.
(E) What do you mean, you had a flat tire?
She appeared momentarily stunned. Then she answered in a hostile way: "What do you mean, 'What do you mean?' A flat tire is a flat tire. That is what I meant. Nothing special. What a crazy question!"
(S) Hi, Ray. How is your girl friend feeling?
(E) What do you mean, "How is she feeling?" Do you mean physical or mental?
(S) I mean how is she feeling? What's the matter with you? (He looked peeved.)
(E) Nothing. Just explain a little clearer what do you mean?
(S) Skip it. How are your Med School applications coming?
(E) What do you mean, "How are they?"
(S) You know what I mean.
(E) I really don't.
(S) What's the matter with you? Are you sick?
"On Friday night my husband and I were watching television. My husband remarked that he was tired. I asked, 'How are you tired? Physically, mentally, or just bored?'"
(S) I don't know, I guess physically, mainly.
(E) You mean that your muscles ache or your bones?
(S) I guess so. Don't be so technical.
(After more watching )
(S) All these old movies have the same kind of old iron bedstead in them.
(E) What do you mean? Do you mean all old movies, or some of them, or just the ones you have seen?
(S) What's the matter with you? You know what I mean.
(E) I wish you would be more specific.
(S) You know what I mean! Drop dead!
During a conversation (with the E's female fiancee) the E questioned the meaning of various words used by the subject . . .
For the first minute and a half the subject responded to the questions as if they were legitimate inquiries. Then she responded with "Why are you asking me those questions?" and repeated this two or three times after each question. She became nervous and jittery, her face and hand movements . . .uncontrolled. She appeared bewildered and complained that I was making her nervous and demanded that I "Stop it". . . . The subject picked up a magazine and covered her face. She put down the magazine and pretended to be engrossed. When asked why she was looking at the magazine she closed her mouth and refused any further remarks.
My friend said to me, "Hurry or we will be late." I asked him what did he mean by late and from what point of view did it have reference. There was a look of perplexity and cynicism on his face. "Why are you asking me such silly questions? Surely I don't have to explain such a statement. What is wrong with you today? Why should I have to stop to analyze such a statement? Everyone understands my statements and you should be no exception!"
The victim waved his hand cheerily.
(S) How are you?
(E) How am I in regard to what? My health, my finances, my school work, my peace of mind, my . . . ?
(S) (Red in the face and suddenly out of control.) Look I was just trying to be polite. Frankly, I don't give a damn how you are.
My friend and I were talking about a man whose overbearing attitude annoyed us. My friend expressed his feeling.
(S) I'm sick of him.
(E) Would you explain what is wrong with you that you are sick?
(S) Are you kidding me? You know what I mean.
(E) Please explain your ailment.
(S) (He listened to me with a puzzled look.) What came over you? We never talk this way, do we?
I have been arguing that a concern for the nature, production, and recognition of reasonable, realistic, and analyzable actions is not the monopoly of philosophers and professional sociologists. Members of a society are concerned as a matter of course and necessarily with these matters both as features and for the socially managed production of their everyday affairs. The study of common sense knowledge and common sense activities consists of treating as problematic phenomena the actual methods whereby members of a society, doing sociology, lay or professional, make the social structures of everyday activities observable. The "rediscovery" of common sense is possible perhaps because professional sociologists, like members, have had too much to do with common sense knowledge of social structures as both a topic and a resource for their inquiries and not enough to do with it only and exclusively as sociology's programmatic topic.
 Karl Mannheim, in his essay "On the Interpretation of 'Weltanschhuung' " (in Essays on the Sociology of Knowledge, trans. and ed. Paul Kecskemeti (New York: Oxford University Press, 1952), pp. 33-83), referred to this work as the "documentary method of interpretation." Its features are detailed in Chapter Three.