Any two expressions are sufficiently equivalent in meaning when they do not diverge demonstrably from the standard usage so as to make it likely that they will be interpreted differently

This principle extends the overall principle of efficient communication to cases where two expressions are compared. Such comparisons arise when the original expression is interpreted in a derived expression (i,e when an expression [EO] is interpreted as another expression [E1]. This occurs in practice in translation between languages or in reformulating statements in any sub-language (i,e. in. terms of a particular thought system or theory) in the terms of another sub-language. Most commonly perhaps, comparison is needed when questioning the meaning of an expression in suggesting how it may be put in other words.

While the principle of appropriateness applies mainly to factors affecting interpretation in respect of the linguistic context and extra-linguistic situation, the principle of sufficient equivalence of meaning applies more to the observance of the meanings commonly or widely attached to terms and expressions, by competent users of the language. In any language there is a fund of historically-accumulated meanings and definitions of terms and expressions that are fairly standardised and without which there would be no basis for anything 'but the most primitive verbal communication. The many variants and nuances of meaning that can arise in specific situations may not be so widespread or standard usage, yet without the standard meanings that form the basis of special uses, (i.e. abbreviations, metaphorical turns of speech, double entendre etc.) the latter could hardly arise at all. No written words, however many terns are coined in it - or however unique and interwoven the meaning it conveys - can be intelligible to a reader without the use of ordinary language and its standard meanings as a basis.

Thus, the principle of appropriateness and that of sufficient equivalence fulfill each other and should be applied together, each to their 'pole' of the sphere of communication.

The present principle assumes that one should stick to the common meanings of terms and expressions where possible and be aware that uncommon uses or direct new coinage of terms can be misinterpreted due to there still being a standard interpretations of them.[ Note: There is the possible exception of the extraordinary 'Finnigan's Wake' - the novel by James Joyce - which uses no ordinary words. But it is notorious for its unintelligibility even to linguists.]

Ideally, the principle would be perfectly fulfilled where two terms or two expressions could be shown to be identical in meaning, that is - 'exactly equivalent'. Exact equivalence in meaning can only be demonstrated - if at all - in the case of highly specialised terminologies or the most common and standardized words in a language. For example, the term 'chair' is probably most often exactly equivalent to the word 'chaise' in French, or the word 'stol' in Norwegian. Yet in different contexts and circumstances, different concepts of a chair might come to mind. So exact equivalence is unlikely in all respects and can only be practically demonstrated in specific communications situations. A 'theoretical demonstration' always runs into the difficulty that we cannot by any normal means know or experience exactly which concepts or assertions come (in) to a person's mind. We have to rely on 'external' behaviour to judge what the person understands by any term or expression, including what they express as their interpretation (i.e. in other terms than the original).

Demonstrable exact equivalence between expressions probably occurs mostly in the so-called 'exact' sciences such as 'pure' mathematics, symbolic logic, theoretical physics and computer languages. This is possible where the meaning of all terms is exactly and their use is regulated strictly by formal rules or axioms. Exact equivalence can certainly arise, provided the interpreter follows the conventions correctly. For example, 'Two plus two equals six minus two'. The logical subject (2+2) and the logical predicate (6-2) can be argued to be exactly equivalent in meaning, though the terms used are different.

Since exact equivalence is seldom demonstrable and since what is sufficiently equivalent will depend upon which likely sources of misinterpretations (due to ambiguity or vagueness in an expression) have been eliminated, it is more pertinent to study cases of insufficient equivalence of meaning than the converse.

Because the expressive possibilities of Ianguage are virtually so unlimited as to make almost any shade of meaning or connotation expressible, exhaustive set of rules ca be set up to cover all the possible cases of insufficient equivalence that can arise between any two terms or expressions. In the last instance, the effective meaning of an expression depends upon how it is intended and interpreted in the communication situation concerned.

Since, however, we are often confronted with statements out of context or else statements whose origin and circumstances of communication are otherwise unknown to us, some general rules can be made as standards against which to test the likelihood of sufficient equivalence of meaning between two expressions.

These rules therefore indicate common sources of error in attempts at making sufficiently equivalent expressions.
The first rule is the main rule because it is the most clear and definitive of the rules that apply and because it has the widest application. The other rules are usually applicable to special cases of infringements of the first rule. In other words, where the first rule applies, one or more of the others will often also apply ... in the same instance. However, since the first rule does not cover all possible cases of insufficient equivalence of meaning between two expressions, other rules can be infringed without the first rule also being demonstrably infringed.

Rule 1 (Main rule) When what one expression asserts can be judged true, while what an interpreted expression of it asserts can be Judged false, then the two are not sufficiently equivalent in meaning

An expression that asserts a true state of affairs cannot mean the same as an expression that asserts a falsity, whatever the communication situation involved. Though two communicators might take two such expressions to mean the same (i.e. one which is false and one which is true), there is not sufficient equivalence in meaning. A demonstrable difference in meaning will remain if one is true and the other false (and if it can be shown conclusively that the one is true and the other false). For example:-

EO "Martin Heidegger wrote the work 'Being and Time'." (True)
E1 "Martin Heidegger wrote the work 'Being and nothingness'." (False)

It can be demonstrated conclusively that Jean-Paul Sartre wrote the work 'Being and Nothingness' and that Heidegger wrote no such work. It is evident at a glance that the two expressions cannot be sufficiently equivalent in meaning to anyone acquainted with the works of Heidegger. Suppose, however, that the work Sein und Zeit had be translated in two versions, one which had mistakenly been entitled 'Being and Nothingness'. Then the two expressions would be intended to refer to the same work by the same author and both would have been true and could have meant the same (the only difference between the two works supposedly being a wrong title on the one).

One does not need to know that one expression makes a true and the other a false assertion, however, for it is adequate to demonstrate that the one could be true while the other could be false to show that there is insufficient equivalence of meaning between two expressions. For example:-

EO "Jean-Paul Sartre wrote about the experience of futility of being."
E1 "Jean-Paul Sartre wrote about the meaning of existence as a free being."

It is quite possible for someone to write about the futility one can experience as a meaning of human existence as free being, and vice-versa. Therefore we see that it is in principle possible for EO to be true while E1 could be false. Also vice-versa: EO could be false while E1 could be true. Therefore one judges the two expressions as not making the same assertion, or in other words, EO and E1 are not sufficiently equivalent in meaning.

It so happens that both EO and E1 are in fact true. This does not alter the case, for they are still insufficiently equivalent in meaning. That two expressions make true assertions is not enough to prove that they obviously mean the same.

Eg: E0 "Sartre was a Frenchman" (True)
E1 "Heidegger was a German" (True)

EO and E1 certainly cannot mean the same, though both are true. In this case, the first (main) rule applies and the principle of sufficient equivalence of meaning is infringed. Rule 4 below further indicates how EO and E1 above are not sufficiently equivalent in meaning (i.e , the two expressions assert something about two different states of affairs).

The principle of sufficient equivalence of meaning is based upon -the normal requirements of standard usage in the language being used. The English language, like any other, can be said to be made up of words and grammatical structures etc. which have, in a sense, 'objectified' meanings. Thus, the term 'Frenchman' has a relatively well-delimited connotation or sense, such as is defined in a dictionary. It cannot, even under extreme circumstances, mean the same as 'German'. In the previous example, where 'Time' and 'Nothingness' were involved, there might occur circumstances in which the two terms -being highly abstract and potentially ambiguous words- cannot be clearly separated from one another as regards their meaning. In a work on metaphysics where the purpose is to deny the objectivity of 'time', it might be equated with 'nothingness'.

Further, many people use language in highly abstract and imprecise ways, particularly in face-to-face situations which permit non-verbal communication. Therefore it is wisest to assume in general that any word, phrase or sentence with which one is dealing in interpretation can be used in ways which seem at first to be at variance with the common meaning(s) or dictionary definitions. The usage in question may depend more on the communication situation at hand, the purposes of the communicators and their peculiar frames of reference, than on the standard usage. (See below "Overall judgement of "likely interpretations")

Rule 2 When an expression contains terms that can convey cognitive meeting that is not derivable from the terms of a similar expression, they will usually not be sufficiently equivalent in meaning

Rule 2 indicates a possible source of divergence between two expressions, but gives no strict standard of non-equivalence.
Eg. E0 "The government will conduct an inquiry into alleged police violence and corruption."
E1 "The government will conduct an independent inquiry into alleged police violence and corruption."

The addition of the term 'independent' in E1 conveys a significant additional cognitive meaning. E1 specifies the type of commission. In some contexts or situations it may be arguable that 'independent' is implicit, that a government commission can implicitly be taken to mean an independent one. Such arguments are to be expected from the government concerned. Nevertheless, the addition of the explicit term 'independent' makes more of a. commitment towards a non-partisan committee, verbally at least. There are therefore grounds for holding that EO and E1 are not sufficiently equivalent in meaning, particularly if they are regarded literally and out of any further context (such as if they were expressed in a news bulletin). The fact that the government will conduct the inquiry itself, however, makes one wonder how 'independent' is to be interpreted. Consider therefore a second example:-
E2 "The government will appoint an independent commission to inquire into police violence and corruption." Comparing this to 21', the addition of 'commission' and the omission of 'alleged' make a considerable difference in the import of the statement. An inquiry conducted by the government would seem likely to be less politically objective than one by an 'appointed independent commission'. In practice this may depend upon who is appointed by whom and under what conditions, yet on paper the difference is significant enough to let one judge that B2 and E1 are not sufficiently equivalent in meaning.
[Note that these infringements of rule 2. also involve infringements of the main rule 1.]

Rule 3 Where one expression allows a more general interpretation than another expression allows, the two are not likely to be sufficiently equivalent in meaning

Eg) EO "Almost all religions have something essential in common" "Some religions have something essential in. common"
The difference in standard contemporary usage of 'almost all' and 'some' are in my judgement close to the difference in meaning between 'a majority of and 'at last a few'. This helps demonstrate that EO and E1 are not sufficiently equivalent in meaning according to standard usage. Further, E0 could be true - while E1 could be false, hence non-equivalence.
Eg: EO "The world at large won't benefit by an economy based on financial profit."

E1 "So trading nations will benefit by an economy based on financial profit".
E0 is evidently more inclusive or general than E1. E0 allows of interpretations that E1 does not allow, because there can be .nations in the world that do not trade and because 'the world at large' can mean all groupings and any individuals, which trading with 'nations' cannot mean. Again, E0 could be true while E1 could be false, and vice-versa.

Rule 4 When one expression refers to a different state of affairs than another, they will not usually be sufficiently equivalent in meaning.
Eg) EO "Our lecturer does not always express himself in the simplest terms
E1 "Our lecturer does not always make himself understood."

Because the state of affairs referred to by E1 could be a consequence of that referred to by EO, they are not necessarily the same. Hence the meaning of both expressions is unlikely to be sufficiently equivalent. It is possible that the two facts asserted are unrelated as using the simplest terms is not the only way of making oneself understood, but also that they are related though different facts.

A special case of rule 4) occurs when one expression refers to a reason, motive or cause when the second refers to an action, consequence or causal effect. The above example is one of the relation between a possible reason and its possible effect or consequence. Because of our habitual acquaintance with typical causes and effects, motives and consequences, we often equate the one with the other as if they 'meant' the same. On closer analysis the cause or motive consists in one state of affairs which is related to another but qualitatively-different state of affairs,,, the effect or result,
Eg) EO "The indigenous peoples of the Amazon basin are being driven from their lands."
E1 "The indigenous peoples of the Amazon basin are being driven into poverty."

Though the second state of affairs follows in almost all cases, so that being driven from their lands 'means' poverty for most of those Indians, the two assertions are not sufficiently equivalent in meaning to, say, the scientific anthropologist, because many other accompanying factors are involved in connecting the two states of affairs.


Overall judgement of 'likely interpretations'

When considering whether expressions are mutually-substitutable without alteration of meaning, taking into account both the principle of appropriateness of expression and that of sufficient equivalence of meaning, certain steps may be followed to decide whether they are likely interpretations of one another.
The term 'likely interpretation' will be used of any derived expression that cannot reasonably be argued to express a different assertion for the communicators or recipients involved

The following questions should be put of derived expressions when comparing them with the original expression of the communicator:-
1) Is the expression (E1, E2 etc.) appropriate to the communication situation? (i.e. is it free of emotive, obscure or incorrect usages?) If no to all questions, it should be altered accordingly before proceeding.

2) Is the expression sufficiently equivalent in meaning to E0 according to standard usage and the rules 1) to 4)? If no, then it must be rejected, for it is not then a likely interpretation, unless 3) below applies:-

3) Can the expression nevertheless be reasonably argued to express the same assertion as the origin expression (E0) when considering the special nature of the actual communication situation and those involved? If yes, then it is a likely interpretation for that communication situation,
Obviously, if 2) can be answered with 'yes', then the expression in question is a likely interpretation of EO.'

In demonstrating a case, giving reasons for one's answer to the above questions, the following sort of arguments can be relevant:-

1) Grounds as to what the communicator is likely to mean judging by the function or purpose of the communication

If the communicator is speaking as a politician, for example, an expression may often be interpreted differently than if the speaker were a religious leader or an entertainer, say. The nature of the audience and even the surroundings may influence the way the same expression is interpreted:-
Eg.) E0 "We must prepare ourselves against harder times ahead."
As a statement regarded independently of other verbal context, the interpretation likely for a politician addressing a trade union meeting might be:-
E1 "We must prepare ourselves for the effects of a deepening economic depression."

For a preacher addressing a congregation, a more likely interpretation would be:-
E2 "We must prepare our souls for the day of judgement."
Note that the additional cognitive meaning that the terns of E1 and E2 does not necessarily make them unlikely interpretations of E0. The communication situation is here used to help interpret the implicit meaning likely in each situation.

2) Arguments as to what state of affairs an expression nay refer (if any).
Where an expression asserts a state of affairs as pertaining it will on occasion be an aid in deciding which interpretation is likely or not, particularly where one can in advance assess which relevant states of affairs do or do not pertain.
Eg) E0: "Prison offenders set their freedom at intervals by going off on holiday".

If one has the information that EO here refers to the practice in certain prisons in Sweden, the term 'on holiday' will be interpreted literally. Were one only to know of prison arrangements in Britain or the U.S.A., for example, 'on holiday' would probably be interpreted as 'escaping from prison until caught again', as the press so humourously often puts it. (i.e. prisoners in Britain and the U.S.A. are not allowed a regular holiday).

3) Arguments for and against the likelihood of an interpretation can also refer to standard usage of terms and expression based on dictionary sources or on the interpreter's own experience.
It may be instructive here to study the terms and grammar from various viewpoints, considering in imagination or memory how different recipients and communicators can derive unusual variants of meaning from them depending upon their varied frames of reference. Obviously, arguments under this point 3) include reference to the main rule and the three subsidiary rules, showing how they might or might not apply in each case.
In reviewing the theory thus far, it should be noticed that the definition of a 'likely interpretation' expresses the chief practical requirement of demonstrating and judging interpretations for what Arne Næss has called their 'reasonability'. It expresses a practical rule for deciding whether one has sufficient theoretical grounds, as well as sufficient empirical grounds, for deciding which interpretations of a given expression can be accepted. The theoretical grounds are represented here by the two main principles - appropriateness and sufficient equivalence.

Interpretations (i.e derived expressions) which are inappropriate to a communication situation and/or those insufficiently equivalent in meaning to the given expression (EO) cannot be likely interpretations of it.
Thus, the judgement that any expression E1 is a likely interpretation of an expression EO summarises the judgements made under the principles of appropriateness of expression and of sufficient equivalence. If E1 introduces inappropriate terms or expressions (i.e. emotive, obscure or ungrammatical elements), then it cannot be judged a likely interpretation of EO. If the first (main) rule of sufficiency of equivalence is not fulfilled, it cannot be a likely interpretation either. If the first rule is satisfied, the two expressions may still be insufficiently equivalent, depending on the actual terms/expressions and the communication situation involved. Arguments for and against sufficiency of equivalence in meaning are not always decisive: i.e. conclusions cannot always be reached. The deciding factor in any judgement of likelihood of interpretations is always ultimately empirical. The specific circumstances of the communication situation in question which lend a term or an expression its nuances of meaning -the context and the purposes of the communication - are empirical. Though these cannot always be investigated adequately, of course, the judgement of likelihood of an interpretation will rest on experience. The interpreter's intuition of what meanings are likely, which senses are relevant to impute to an expression, will rest upon the interpreter's own experience of similar situations and language uses... so the judgement is still empirical in this broad sense of the term.
Note that 'likely interpretation' is a reciprocal relationship between two expressions such that, if E1 is judged a likely interpretation of E0, then EO must also be a likely interpretation of E1. This can be understood simply be considering that, for example, EO "I enjoy fresh air" is likely to mean the same as E1 "I like fresh air". Then E1 must also be likely to mean the same as EO.
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EXERCISES (SUFFICIENT EQUIVALENCE OF MEANING & LIKELY INTERPRETATION)

1) Consider whether the two following expressions from a discussion on the filmatisation of a great novel are sufficiently equivalent in meaning:-
EO "The book is always better than the film".
E1 "The film is seldom quite as good as the book".
Consider also which of the two expressions above is sufficiently equivalent in meaning to the following:-
E2 "Never is the book less good than the film". Explain the principle of sufficient equivalence of meaning as part of your answer.

2) Consider whether the two following expressions are sufficiently equivalent in meaning, giving grounds for your answer:-
EO "It's unlikely that a nuclear war will occur".
E1 "It's quite possible that a nuclear war will occur".
Further consider whether the following E2 would be sufficiently equivalent to either of the above:-
E2 "It is not impossible that a nuclear war will be started".

3) EO "Dogs with erect tails are more often attacked by other dogs than are those with lowered tails".
El "Dogs with lowered tails are less often attacked by other dogs than are those whose tails are erect".
Are the two above expressions sufficiently equivalent in meaning? In giving grounds, consider whether any of the rules for judging sufficient equivalence are broken.

4) Suppose a political debate on the question of how much real unemployment exists in your country leads to the following two expressions:-
EO "There are a considerable and quite unacceptable number of unemployed".
E1 "There are a considerable number who register for unemployment benefit, which is quite unacceptably high".
Suppose that the speaker who said E1 holds this to state the same as what his opponent said by EO? Do you agree that these two expressions can refer to the same state of affairs and otherwise be regarded as sufficiently equivalent in meaning? Give grounds for your answer.

5) EO "The artificially-high price of most goods in this country is due to State protection of national firms in the interest of profitability".
E1 "The excessive prices of most products in this country are due to official protection of national monopolies in the interests of high profits".
Give reasons why E1 cannot be accepted as a likely interpretation of EO.

6) Consider the following exchange of views between A and B;-
A: The students should be more critical
B: What's the point of that? One should rather encourage them to see the positive sides of an issue, not the negative ones.
A: I mean that one should train students to see both the positive and negative sides of an issue and, on the basis of that, to make a considered judgement. That would make them less susceptible to the propaganda of political ideologies.
a) State how A. and B. respectively interpret the term 'critical' in A's first statement.
b) Consider whether you find both A's and B's interpretations to be likely interpretations of the term 'critical', giving reasons.
c) Do you further consider A's own interpretation of 'critical' to be a likely interpretation of B's interpretation of 'critical'? Give grounds.