[N]o philosophical analysis of the meaning of any term worth so analysing can ever leave things exactly as they were—however conservative the intentions and protestations of its protagonists. For it must necessarily tend to change the meaning for us and our usage of the terms it analyses—ideally by precisifying it and making clear its implications.
(ii) I propose, therefore, that we take as parts of the meaning of "punishment", in the primary sense, at least five elements. First, it must be an evil, an unpleasantness, to the victim. By saying "evil"—following Hobbes—or "unpleasantness" not "pain", the suggestion of floggings and other forms of physical torture is avoided. Perhaps this was once an essential part of the meaning of the word, but for most people now its employment is less restricted. Note in this connection the development of an historically secondary use of the word; as applied first to a battering in boxing, then extended to similar situations in other sports where there is no element of physical pain (e.g. as an equivalent to "trouncing", of bowling in cricket).
Second, it must (at least be supposed to) be for an offence. A term in an old-fashioned public school, though doubtless far less agreeable than a spell in a modern prison, cannot be called a punishment, unless it was for an offence (unless perhaps the victim was despatched there for disobedience at home). Conversely, as Mabbott most usefully stresses, if a victim forgives an offender for an injury which was also an offence against some law or rule, this will not necessarily be allowed as relevant to questions about his punishment by the institution whose law or rule it is. A mnemonic in the 'material mode of speech': "Injuries can be forgiven; crimes can only be pardoned".
Third, it must (at least be supposed to) be of the offender. The insistence on these first three elements can be supported by straightforward appeal to the Concise Oxford Dictionary, which defines "punish" as "cause (offender) to suffer for an offence".
Notice here that though it would be pedantic to insist in single cases that people (logically) cannot be punished for what they have not done; still a system of inflicting unpleasantness on scapegoats—even if they are pretended to be offenders—could scarcely be called a system of punishment at all. Or rather—to put it more practically and more tolerantly—if the word "punishment" is used in this way, as it constantly is, especially by anthropologists and psychoanalysts, we and they should be alert to the fact that it is then used in a metaphorical, secondary, or non-standard sense: in which it necessarily has appropriately shifted logical syntax (that is: the word in this case carries different implications from those it carries in a standard case of its primary sense). A likely source of trouble and confusion.
Fourth, it must be the work of personal agencies. Evils occurring to people as the result of misbehaviour, but not by human agency, may be called penalties but not punishments: thus unwanted children and venereal disease may be the (frequently avoided) penalties of, but not the punishments for, sexual promiscuity. To the extent that anyone believes in a personal God with strong views against such sexual behaviour, to that extent he may speak of these as divinely instituted punishments (though, allowing the linguistic propriety of this, the fact that so often the punishments fall on the innocent and can be escaped by the guilty should give pause still).
(Note here. First the distinction often and usefully made—but rarely noticed even by those making it—between the 'natural' penalties of and the prescribed penalties for such and such conduct (gout of port-bibbing: free kicks for fouls). Second, that the expression "to the extent that" is peculiarly appropriate to beliefs about God and a quasi-personally sustained moral order in the universe: for with most people these meander somewhere between complete conviction and complete disbelief; and hence to offer the present distinctions between the uses of "punishment", "penalty of" and "penalty for" as if these were already completely given in present (correct) usage would be seriously to misdescribe the confused situation which actually confronts us.)
Fifth, in a standard case punishment has to (be at least supposed to) be imposed by virtue of some special authority, conferred through or by the institutions against the laws or rules of which the offence has been committed. Mabbott brought this out clearly. A parent, a Dean of a College, a Court of Law, even perhaps an umpire or a referee, acting as such, can be said to impose a punishment; but direct action by an aggrieved person with no pretensions to special authority is not properly called punishment, but revenge. (Vendetta is a form of institutionalized revenge between families regarded as individuals.) Direct action by an unauthorized busybody who takes it upon himself to punish, might be called punishment—as there is no unanimity rule about the simultaneous satisfaction of all the criteria—though if so it would be a non-standard case of punishment. Or it might equally well be called pretending (i.e. claiming falsely) to punish. The insistence on these fourth and fifth criteria can be supported by appeal to the Oxford English Dictionary which prefaces that same definition as that given in the C.O.D. with "As an act of superior or public authority".
Besides these five positive criteria I propose negatively that we should not insist: either that it is confined to either legal or moral offences, but instead allow the use of the word in connection with any system of rules or laws—State, school, moral, trades union, trade association, etc.; or that it cannot properly be applied to morally or legally questionable cases to which it would otherwise seem applicable, but instead allow that punishments, say, under retrospective or immoral laws may be called punishments, however improper or undesirable the proceedings may be in other respects. Laxity in both these directions conforms with normal usage; while in the second it has the merit of separating ethical from verbal issues.
(Antony Flew, "'The Justification of Punishment,'" Philosophy 29 [October 1954]: 291-307, at 293-5 [italics in original; footnote omitted])
Note from KBJ: One might summarize Flew's analysis of the concept of punishment by saying that punishment is harsh treatment of an offender, by an authority, for an offense.