Information Reports

Julio Ostalé
Incorporated contributions
Ostalé (18/12/09)
Usage domain
semantics, situation theory
rapports d'information
German Informationsberichte


1. Definition

2. Remarks

3. Methodological relevance

4. Examples

1. Definition

In a broad sense, an information report is one of these two things: (i) A report in which either the noun "information" or the verb "to inform" or the adjective "informative" or some other derivative appears. (ii) A report that can be paraphrased into a report of the first sort.

Examples: "a informs to b about p", "database DB1 contains more information than database DB2", "information source S1 is less reliable than information source S2", "it is illegal that a conceals from b the information p".

In a narrow sense, an information report is any report that (iii) either exhibits the form "signal s carries the information p", (iv) or can be rephrased in such a form.

2. Remarks

We are not dealing with standard defitinitons as there is not a well established theory on information reports and their semantics. The definition in a broad sense tries to gather diverse contributions of the technical literature since at least Fox (1983).

An information report in a narrow sense is but a variety of information report in a broad sense. But the influence of Israel and Perry (1991), where the former are defined, justifies the distinction.

The reduction from (ii) to (i) and from (iv) to (iii) is not always so clear, therefore it is convenient to center on (i) and (iii) up to grasping well the information concept. However, there are clear cases of possible reduction, as it happens with reports like "s means p" as they are studied in Grice (1957) or Barwise and Perry (1983).

3. Methodological relevance

In analytical philosophy it is usually argued for (Fox 1983: 20-29) that any conceptual investigation on information must begin with a prior study regarding information reports. This does not imply resigning from the study of concepts and realities in favor of a mere study of language. The strategy is to take the language as a starting point. First it is agreed that reality X is the meaning of expression "X". Then the linguistic uses of "X" are discussed, since this is a more objective field than that of the direct discussion about X. Finally we come back to the study of X, this time from an intersubjective agreement and conceptual delimitation that stems from the previous discussion about the uses of "X".

4. Examples

Since there is no standard theory regarding information reports, it is more secure to introduce them trough concrete examples instead of displaying from the very beginning a tentative classification. Let's see two of them. The first one comes from Israel and Perry (1991), the second from Floridi (2006). The former example assumes some knowledge on propositional attitude reports (McKay y Nelson 2008). The latter requires some basics on modal epistemic logic (Hendricks and Symons 2009).

Example 1: "signal s carries the information that p"

Israel and Perry (1991) devotes its first section to the logical-linguistic study of information reports. Paradigmatic examples are:

(1) "The x-rays indicates that Jackie has a broken leg."

(2) "The fact that the x-ray has such and such a pattern indicates that Jackie has a broken leg".

Both in (1) and in (2) the initial noun phrase plus the verb or verb phrase form the informational context; the proposition designated by the that-clause is the informational content. The object designated by the initial noun phrase of (1) is the carrier of the information; the fact designated by the initial noun phrase of (2) is the indicating fact.

Some important properties of informational contexts:
  • They are factive: if an information report is true, its informational content is true too.
  • They are not truth-functional: given "s informs that p" and the logical equivalence between p and q, one does not conclude "s informs that q".
  • They distribute across conjunction: if "s informs that p and q", then "s informs that p and s informs that q".
  • They do not distribute across disjunction: given "s informs that p or q", one does not conclude "s informs that p or s informs that q".
  • They are opaque with respect to definite descriptions: given "s informs that c holds the property P" and the equality c = "the x that holds Q", one does not conclude "s informs that the x that holds Q also holds P".
Some analyses of information reports based on Israel and Perry (1991), like e.g. Barwise and Seligman (1997: 12-13), take any report of type (1) to be an abbreviation of some report of type (2). Such analyses are usually based on Dretske (1981).

Example 2: "agent a is informed that p"

Floridi (2006) establishes three different ways in which an agent a can be related to an information piece p, the latter being a contingently true proposition. These three relations can be seen like interpretations of the expression "the agent a is informed about p".
  • Being informative: Evaluation of that situation in which p brings information to the agent.
  • Becoming informed: The process by which the agent gets the information p. The result of this process is the situation in which the agent is informed.
  • Being informed: The cognitive state of the agent by virtue of which it possesses the information p. It can be seen as the result of the action of becoming informed.
Of these three interpretations Floridi (2006) focuses only on the third one. He wonders if there exist modal logics whose modal operator Iap could be read as "the agent a is informed that p". If that is the case, those logics would be comparable to the modal doxastic logics KD, KD4 and KD45 (where Bap means that a believes that p), as well as to the modal epistemic logics KT, S4 and S5 (where Kap means that a knows that p). The proposal of Floridi (2006) is to interpret the modal logic KTB as the best formal model for the relation of "being informed".
  • BARWISE, J. & PERRY, J. (1983). Situations and Attitudes. Cambridge: Cambridge (Massachusetts): The MIT Press.
  • BARWISE, J. & SELIGMAN, J. (1997). Information Flow. The Logic of Distributed Systems. Cambridge: Cambridge University Press.
  • DRETSKE, F. I. (1981). Knowledge and the Flow of Information. Cambridge (Massachusetts): The MIT Press.
  • FLORIDI, L. (2006). "The logic of being informed". Logique et Analyse, Vol. 49(196), pp. 433-460.
  • FOX, C. J. (1983). Information and Misinformation. An Investigation of the Notions of Information, Misinformation, Informing, and Misinforming. Westport (Connecticut): Greenwood Press.
  • GRICE, P. (1957). "Meaning". The Philosophical Review, Vol. 66, pp. 377-388.
  • HENDRICKS, V. & SYMONS, J. (2009). Epistemic Logic. [Online]. Stanford: The Stanford Encyclopedia of Philosophy (Spring 2009 Edition). <>. [Consulted: 18/12/2009].
  • ISRAEL, D. & PERRY, J. (1991). "What is information?". In Philip Hanson (ed.). Information, Language and Cognition. Vancouver: University of British Columbia.
  • McKAY, T. & NELSON, M. (2008). Propositional Attitude Reports. [Online]. Stanford: The Stanford Encyclopedia of Philosophy (Fall 2008 Edition). <>. [Consulted: 18/12/2009].
Ostalé, Julio (18/12/09)

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