Legal Theory Lexicon

Legal Theory Lexicon 066: Baselines

reIntroduction

Most undergraduates are likely to become acquainted with John Stuart Mill's famous harm principle at some point.  Here is how he stated the principle in On Liberty:

The object of this Essay is to assert one very simple principle, as entitled to govern absolutely the dealings of society with the individual in the way of compulsion and control, whether the means used be physical force in the form of legal penalties, or the moral coercion of public opinion. That principle is, that the sole end for which mankind are warranted, individually or collectively, in interfering with the liberty of action of any of their number, is self-protection. That the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others. His own good, either physical or moral, is not sufficient warrant. He cannot rightfully be compelled to do or forbear because it will be better for him to do so, because it will make him happier, because, in the opinion of others, to do so would be wise, or even right... The only part of the conduct of anyone, for which he is amenable to society, is that which concerns others. In the part which merely concerns himself, his independence is, of right, absolute. Over himself, over his own body and mind, the individual is sovereign.

The harm principle is itself a fascinating topic (perhaps for another Lexicon entry), but on this occasion, we are using it to ask the question: what constitutes harm to others?  Of course, we can all enumerated examples of harm.  Alice kicks Ben in the shin and bruises him.  Carla steals David's lunch.  Edwina falsely accues Frank of plagerism.  But all of these examples assume that we can distinguish what the infliction of harm from something else--the denial of a privilege or advantage.  Gertrude denies Harry a job.  Ingrid decides not to invite Jim to her party.  Karl refuses to share his collection of MP3 files with Laurie.  Are these harms or not?

The problem of distinguishing harm from denial of advantage or rights from privileges involves one of the most interesting concepts in legal theory--the notion of a baseline.  This entry in the Legal Theory Lexicon introduces to the baseline problem.  As always, the Lexicon is aimed at law students, especially first-year students, with an interest in legal theory.

The Function of a Baseline

A variety of important legal concepts are relative in the following sense: an action, event, or state of affairs falls under the concept by comparison to some alternative.  Mill's idea of "harm" has this property: an event is a "harming" only in comparison to some prior or alternative state of affairs.  A similar point could be made about "injury," "advantage," "benefit," and similar terms.

There is where the notion of a baseline comes in.  For example, we might use a temporal baseline to define harm: action X is a harm to individual P if and only if P is worse off after X and this change in welfare is causally produced by X.  This sounds plausible, but it isn't difficult to cook up examples where this formula doesn't match our intuitive understanding of harm.  Mary asks Nancy to repay a $10 loan, and Nancy agrees to do so. Nancy is worse off, but it isn't clear that Mary has harmed Nancy--even though her request for payment is the cause of Nancy's being worse off (financially) than she was before the request for repayment. A similar point could be made about advantage. Mary forgives Nancy’s debt. Nancy's financial circumstances aren't improved relative to a temporal baseline, but we might believe that Mary has conferred an advantage on Nancy. In both examples, the temporal baseline doesn't capture our intuitive sense that the relevant baseline ought to be defined in terms of Mary and Nancy's respective entitlements.

Possible Legal Baselines

So how could the law identify baselines?  Let's just list a few possibilities:

Positive Entitlements: The law could take one's existing entitlements (as defined by the positive law) as the baseline for measuring legal harm or advantage.

Common law: Another option would be to take the common law system of property, contract, and tort law as the definition of baseline entitlements.  Official actions that worsened an individual's position relative to the common-law baseline could be defined as harms, and actions that bettered the common-law baseline could be defined as advantages.

Natural rights: Yet another possibility would be the the baseline could be defined by a theory of natural rights.  One such theory is offered by theories of the state of nature and the social contract.  The baseline of natural rights could be identified with those rights that would be retained by rational individuals who agreed to enter into civil society from a state of nature.

Human rights: Another source of a baseline might be the bundle of entitlements identified by international human rights law.

At this point, I'm sure that Lexicon readers will have recognized that the identification of a baseline can be crucially important to answering the question whether an injury has occurred.  If positive law identifies the baseline, then there are no injuries unless a legal entitlement is violated.  But if natural right sets the baseline, then there can be injury without violation of the positive law.

Contexts in which Baselines Matter

Baselines are important in a variety of contexts.  How do we distinguish offers from threats?  Nozick's clever distinction is that a threat is an offer you would rather not receive, but underlying his point is the notion of a baseline.

Baselines are have played an especially prominent role in constitutional theory.  In that context, the baseline problem is strongly associated with Cass Sunstein, and especially with his analysis of the United States Supreme Court's decision in Lochner v. New York.  As most readers of the Lexicon will know, the Supreme Court invalidated a New York statute that regulated the number of hours that could be worked by bakers on the basis of the due process clause of the 14th Amendment of the United States Constitution.  The statute was challenged on the basis that it deprived bakery owners of liberty.  The question is what determines the baseline.  Sustein argued that the Court had erroneously assumed that the common-law provides a natural baseline, when in fact the system of common-law rights is itself a product of positive law and hence subject to redefinition by legislative action.  The following passage provides the flavor of Sunstein's argument:

The Lochner Court required government neutrality and was skeptical of government “intervention”; it defined both notions in terms of whether the state had threatened to alter the common law distribution of entitlements and wealth, which was taken to be a part of nature rather than a legal construct. Once the common law system came to be seen as a product of legal rules, the baseline from which constitutional decisions were made had to shift. When the Lochner framework was abandoned in West Coast Hotel, the common law system itself appeared to be a subsidy to employers. The West Coast Hotel Court thus adopted an alternative baseline and rejected Lochner era understandings of neutrality and action. (Sunstein, Lochner's Legacy, p. 917)

Of course, the system of common-law rights could be used as a baseline.  Sunstein's point is that the common-law is not more "natural" than any other baseline derived from the positive law.

One can imagine a variety of replies to Sunstein's argument.  One possibility is to argue that the common-law system of rights does have some special statues.  For example, it might be argued that common-law property, contract, and tort rights instantiate a system of natural rights.  Or it might be argued that the common law reflects deeply held and wide shared social norms that provide the content of a shared social sense of justice.  Whether arguments like this will succeed on the merits is certainly contestable, but for your purpose the important point is that baselines must be justified--they cannot just be assumed.

Conclusion

Concepts like harm, injury, advantage, and benefit are pervasive in legal theory.  Understanding these concepts requires an appreciation of the baseline problem.  The pont of this Lexicon entry is to give the reader a basic understanding of what baselines are and how they can be challenged and defended.  Of course, there is much more to be said, and the bibliograph provides some additional sources to investigate.

Bibliography

Jack M. Beerman & Joseph William Singer, Baseline Questions in Legal Reasoning: The Example of Property in Jobs, 23 Ga. L. Rev. 911 (1989).

David E. Bernstein, Lochner's Legaacy's Legacy, 82 Tex. L. Rev. 1 (2003).

Cass Sunstein, Lochner's Legacy, 87 Colum. L. Rev. 873 (1987).

Cass Sunstein, After the Rights Revolution: Civil Rights, Environmental Law, and Statutory Interpretation (Harvard University Press 1990).

(This entry was last revised on May 26, 2008. My thanks to Kenneth Simons for his comments.)

Legal Theory Lexicon 065: The Nature of Law

Introduction

What is the nature of law?  This question has occupired center stage jurisprudence and philosophy of law in the modern era, and has been the central occupation of contemporary analytic jurispurdence.  This entry in the Legal Theory Lexicon aims to give an overview of the "What is Law?" debate, with more specialized entries on specific aspects of the debate to follow over the next several weeks.

Historically, the answer to the question, "What is law?," is thought to have two competing answers.  The classical answer is provided by natural law theory, which is frequently characterized as asserting that there is an essential relationship between law and morality or justice.  The modern answer is provided by legal positivisim, which, as developed by John Austin, asserted that law is the command of the sovereign backed by the threat of punishment.

Contemporary debates over the nature of law focus on a revised set of positions.  Legal positivism is represented by analytic legal positivists, like H.L.A. Hart, Joseph Raz, and Jules Coleman.  The natural law tradition is defended by John Finnis.  And a new positition, interpretivism is represented by Ronald Dworkin.

In some ways, the title of this Lexicon entry is misleading, because of our focus on the "What is law?" question as it has been approached by contemporary legal philosophers.  There are other important perspectives on the nature of law that focus on law's functions rather than the the meaning of the concept or the criteria of legal validity.  For example, the sociological tradition includes important work on the nature of law by Max Weber and Niklas Luhmann.  These issues are discussed by Brian Tamanaha in the article cited in the Links section at the end of this entry.

This Lexicon entry maps the territory of the "What is Law?" controversy, and provides introductory sketches to the major positions.  As always, the Lexicon is written for law students, especially first-year law students, with an interest in legal theory.

Natural Law Theory

Natural law theory is strongly associated with classical and medieval thought, especially Aristotle, Roman jurisprudence, and St. Thomas Aquinas.  There are several challenges associated with the task of explicating natural law theory, and one of the most important tasks of this introductory entry is simply to identify these challenges.

First, there are two interrelated but distinct views that are called "natural law theory."  One is a view about the nature of morality: this view asserts that there are natural moral laws, and it is not essential to this view that it take any particular stand on the "What is law?" debate.  A second view that is called "natural law theory" is a theory about "law" as an institution or practice--that is the view that is implicated in the "What is law"" controversy.

Second, contemporary understandings of "natural law theory" have been strongly influenced by the legal positivists critique.  When the positivists articulated the theory they were criticizing, their articulations of natural law theory were neither charitable nor true to the natural law tradition.

For the purposes of this broad overview, we might use the latin phrase lex injusta est non lex as a starting point.  Natural law theory could be understood as affirming something like the following:

An unjust "law" is not a true law.

This formulation differs from a literal translation--an unjust law is not a law.  Formulated in that way, natural law theory seems to be committed to a contradiction: something which is a law (but also is unjust) is not a law.  The quotaton marks around "law" and the phrase true law make it clear that natural law theory is asserting something else, that something which might be called a "law" is not in fact a law if it is unjust.  Usually, this notion is accompanied by some explication of the characteristics that are required for status as a "true law" or perhaps "valid law."

Legal Positivism

It is difficult to know where the positivist tradition begins.  Hobbes's theory of law shares some characteristics with the theories offered by Jeremy Bentham and John Austin--both of whom are clearly in the positivist tradition.  Jeremy Bentham developed a very sophisticated version of legal positivism, but for a variety of reasons, the more influential and widely known view was that of Bentham's student, John Austin, the author of The Province of Jurispudence Determined (1861).

Austin's theory was that a given rule was a law if and only if the rule was the command of the sovereign to subjects of that sovereign backed by the threat of punishment.  A sovereign is some person or institution who is habitually obeyed in a well-defined territory, but who or which does not habitually obey any other person or institution.

Austin's positivist theory does an excellent job of explaining the rules of criminal law, which forbid certain actions and impose punishments on those who engage in the forbidden actions.  But this theory has a difficult time accounting for other aspects of law, and especially for those rules that create legal powers, such as the power to create contracts, trusts, wills, and so forth.  This difficulty is most acute with respect to rules that define the basic institutional arrangements that define the sovereign itself, e.g., the rules of constitutional law in the United States.

These deficiencies in Austin's theory prompted H.L.A. Hart to develop a more sophisticated version of legal positivism.  One feature of that theory is the distinction between primary rules (which would include criminal prohibitions) and secondary rules (which allow for the creation, alteration, and termination of primary rules).  Hart replaced the notion of a sovereign with that of a rule of recognition--a social rule that specifies what counts as a law and what does not.

Moral Facts, Social Facts, and Legal Content

The contemporary approach to these issues is the product of almost sixty years of thinking within the tradition that is sometimes called "analytic jurisprudence."  Beginning with the work of H.L.A. Hart in the 1950s, through is publication of The Concept of Law in 1961, and extending through Ronald Dworkin's critique of Hart, and the reformulation of the positivist tradition by both Joseph Raz and Jules Coleman, the basic issues and questions have gone through several transformations.

One useful way to get get at the heart of these developments is to conceive of the debate about the nature of law as centrally concerned with the relationship between social facts, moral facts, and legal content.  Our question is "What determines legal content?," where "legal content" is simply understood as the content of the legal norms.

One answer to this question takes the form: It is necessarily the case that only social facts determine legal content.  This is exclusive legal positivism--a view that is strongly associated with Joseph Raz.

A second answer to this question takes the form: It possibly the case that moral facts determine legal content, but only if social facts give the moral facts this role.  This is inclusive legal positivism--and this view is most strongly associated with Jules Coleman.

A third answer to the question takes the form: It is necessarily the case that moral facts determine legal content.  This view would include natural law theory and interpretivism--the view that is strongly associated with Ronald Dworkin.

By framing the "What is law?" debate in terms of the relationship between social facts, moral facts, and legal content, the conceptual space we get precise mapping of the conceptual space.  In the rest of this Lexicon entry, we will take a somewhat less shallow look at the three options.

Inclusive and Exclusive Legal Positivism

Exclusive legal positivism is the view that only social facts can determine legal content.  Joseph Raz famously argued for exclusive legal positivism based on the premise that law claims authority, that authority consists in displacing other reasons for actions, and therefore law must displace moral reasons for action.  (That was a very short and inadequate summary of a long and complex argument.)

Inclusive legal positivism is the view that moral facts can play a role in determining legal content, but only if there are some social facts that give the moral facts this role.  For example, a constitution might include an clause that make a moral conception of human equality a legal rule.  This would give the morality of equality a role in determining legal rights, but this role would exist because a social fact (the Constitution) made it so.

Interpretivism

The final view is "interpretivism," strongly associated with Ronald Dworkin.  For Dworkin, social facts, such as constitutons, statutes, and court decisions, do not directly determine legal content.  Instead, Dworkin believes that the content of the law is given by the theory that best fits and justifies the legal materials.  Dworkin makes this theory vivid by imagining a judge, Hercules, who is able to construct a grand theory of political morality that provides a constructive interpretation of the entire institutional history of a given society.  Because this theory is a theory of that institutional history, it is constrained.  For example, the best constructive interpretation of the institutional history of the United States will have to acknowledge that our federal legislature is bicameral and that it includes a Senate with equal reprsentation of each state.  But this constraint does not require a perfect match between a literal interpretation of every legal text and the content of the law.  So some precedents may be categorized as mistakes, and some statutory or constituitonal provisions may be given a constructive interpretation that makes them morally more attractive but does not follow every jot and tittle of the text.

Conclusion

This very brief introduction to the "What is law?" debate is necessarily incomplete and shallow.  But I hope that it gives you a general sense of the various positions that have been taken on the nature of law.

Bibliography

John Austin, The Province of Jurisprudence Determined (1861).

Jules Coleman, The Practice of Principle: In Defence of a Pragmatist Approach to Legal Theory (2001).

Ronald Dworkin, Law's Empire (1986).

John Finnis, Natural Law and Natural Rights (1980).

H.L.A. Hart, The Concept of Law (1961) (2d ed. 1984).

Joseph Raz, The Authority of Law: Essays on Law and Morality (1983).

Links

John Finnis, Natural Law Theories, Stanford Encyclopedia of Philosophy.

Leslie Green, Legal Obligation and Authority, Stanford Encyclopedia of Philosophy

Leslie Green, Legal Positivism, Stanford Encyclopedia of Philosophy.

Andrei Marmour, The Nature of Law, Stanford Encyclopedia of Philosophy.

Nicos Stavropoulos, Interpretivist Theories of Law, Stanford Encyclopedia of Law.

Brian Tamanaha, Law, Oxford International Encyclopedia of Legal History, 2008.

Related Legal Theory Lexicon Entries

Legal Theory Lexicon 032: Fit and Justification

Legal Theory Lexicon 038: The Internal Point of View

Legal Theory Lexicon 039: Primary and Secondary Rules

Legal Theory Lexicon 044: Legal Theory, Jurisprudence, and the Philosophy of Law

Legal Theory Lexicon 064: Possibility and Necessity

Introduction What policy choices are feasible and which options are "pie in the sky," "utopian," or "politically impossible"?  What is "necessary" and what is merely probable?  The Legal Theory Lexicon includes two entries that deal with aspects of these questons Legal Theory Lexicon 011: Second Best and Legal Theory Lexicon 062: Path Dependency.  In this post, we will investigate the concepts of "possibility" and "necessity."  These ideas are ubiquitious in theoretical discourse, but they are rarely defined or explicated.  One way to get clear about possibility and necessity is via the power philosophical idea of a possible world, made famous by Leibniz and deployed in contemporary metaphysics by Saul Kripke and others.

As always, the Legal Theory Lexicon is aimed at law students, especially first year law students with an interest in legal theory.  Although "possible worlds" talk may sound complex, the core ideas and terminology can easily be mastered.

Modality Before proceeding any further, we need to introduce an important term, the adjective "modal" and its noun form "modality."  These words are probably unfamiliar to anyone who wasn't a philosophy major, but you may dimly recall that "could" and "must" are called "modal verbs" in texts on English grammer.  "Could" is a modal verb because it expresses possibility: if something could happen, it is possible.  "Must" is a modal verby because it expresses necessity: if something must happen, it is necessary.  When I use the word "modality" in this post, I am simply referring to the general concept that includes both necessity and possibility in all their forms.

Possible Worlds Semantics  The phrase "possible worlds semantics" sounds pretty intimidating, but it is really based on a very intuitive and simple set of ideas.  Possible worlds talk translates talk about possibility and necessity into talk about possible worlds.

Begin with the notion of a possible world. This notion is similar to the notion of a "state of affairs," which may be familiar from economics. The philosophical idea of a "possible world," is understood as a complete history of a whole universe. If some thing is possible, say event X, we say that X occurs in some possible world. Complimentary to the concept of possibility is the concept of necessity. Let us say that an event Y is necessary if Y occurs in all possible worlds; a proposition, p, is a necessary truth if it is true in all possible worlds.

The next step is to add the notion of the "actual world," where actual is an indexical term that separates this world from all possible worlds.  You may not be familiar with the idea of indexical terms.  "Here" is an indexical: its meaning is indexed to the place where the word is uttered.  Likeise, "now" is an indexical: Its meaning is indexed to the time the word "now" uttered.  The actual world is the possible world that we inhabit.

Varities of Possibility  Now that we have the idea of a possible world in place, we can talk about different kinds of possibility.  For example, "logical possibility" requires only logical consistency, and, in the logical sense, possibility is rarely implicated by debates in normative legal theory.  That is because, almost anything that legal theorists would care to talk about is logically possible: it is logically possible that the Constitution will be amended next year to abolish the Electoral College and eliminate the Senate, but no one thinks that these possibilities are even worth discussing in that time frame.

Practical Possibility  The notion that there are different types of possibility can be made very precise by using the notion of a possible world.  Let's try to develop a concept of "practical possibility" that captures the claims made by legal theorists that same legal options are not in the feasible choice set.  We can do this by narrowing the set of possible worlds that are the domain of legal necessity in a series of steps.

Each step can be expressed in terms of the idea of an accessibility relation. The phrase "accessibility relation" may sound obscure, but an example will make it crystal clear. For practical purposes, normative constitutional theory may sometimes only be interested in those worlds that are possible future states of the actual world. Such worlds share the history of the actual world up to this moment, and we call worlds that have this property "historically accessible" from the actual world.  Notice that talk about historical accessibility frequently can be translated into talk about "path dependency."  The feasible choice set--the future choices that are possible--may be (or is) constrained by history.

But "historical accessibility" is not a sufficient limitation for the purposes of normative legal theory. Why not? Because it is logically possible that the future states of the actual world could be just about anything you can imagine; there is no logical contradiction in a possible world that shares the history of the world up until now but in which the United States instantly becomes a parliamentary democracy at the next snap of Jeremy Waldron's fingers. For the purposes of normative legal theory, we should restrict the domain of possible worlds to those that share the basic laws of nature (physics, etc.) with the actual world; these worlds are called "nomologically accessible."  In nomologically accessible worlds, Waldron's finger snaps do not produce constitutional revolutions. The historically and nomologically accessible worlds, then, are those that share the history of the actual world up to now and that share our laws of nature.

At this point it is useful to introduce the idea of "distance" between the actual world and some possible world. Adjacent possible worlds are "close" to the actual world. A possible world that was just like the actual world, except that this entry in the Legal Theory Lexicon was never written, would be very close, i.e., adjacent, to the actual world.  Remote worlds are "distant" from the actual world. A possible world in which complete essays appear without effort, simply by wishing upon a star would be more remote. Even more distant worlds are easy to imagine. In ascending degree of remoteness, we can imagine a world in which the Mongols conquered Europe and the Renaissance did not occur, a world in which humans never evolved, or a world in which subtle variations in physical laws made the evolution of carbon-based life impossible.

The possibilities that concern normative legal theory are primarily those that exist in historically and nomologically accessible possible worlds that are adjacent to the actual world. One set of accessibility relationships is especially relevant to legal discourse: these relationships concern human psychology, institutional capacities, social norms, and political attitudes. Some legal options will not work, given what is true about human psychology: they make unrealistic assumptions about what officials or citizens are capable of doing. Other legal options would require dramatic changes in social norms: their success relies on unrealistic assumptions about what citizens and officials believe is acceptable or unacceptable conduct. Some options make counterfactual assumptions about institutional capacities. And yet other constitutional options are politically infeasible: they presuppose political attitudes that only exist in possible worlds that are remote from the actual world.

But normative legal discourse requires what we might call "normative space."  That is, normative discourse assumes that minds can be changed and the attitudes are not entirely fixed. We can call worlds that conform to the laws of psychology and political science but in which attitudes and beliefs are not fixed "psychologically and politically accessible worlds."

Practically Accessible Possible Worlds Sometimes normative legal theory has practical aims: it is concerned with how we should act in the actual world. Let us call constitutional action in the actual world "legal practice."  Legal practice is not concerned with historically and nomologically accessible possible worlds that cannot come into being given the limits on human choices. If there is nothing that any agent (individual, institutional, or collective) does in any historically and nomologically accessible world that brings a future state of the world about, then the future state is outside the feasible choice set. Let us call the worlds that are open to human choice in the sense just specified "practically accessible."  A practically accessible world must be nomologically and historically accessible through human agency. Legal practice is, by stipulation, concerned with possible worlds that are practically accessible.

Epistemological Accessibility One final accessibility relation requires a brief mention. We can distinguish between those worlds that are consistent with our knowledge of the actual world and those which are inconsistent with such knowledge. We can use the phrase "epistemologically accessible" to capture this idea. Worlds that are consistent with everything we know about the actual world are epistemologically accessible. Worlds that have a feature contradicted by our knowledge of the actual world are epistemologically inaccessible. Not all epistemologically accessible worlds are nomologically and historically accessible; there may be historical facts or natural laws of which we are unaware.

The Feasible Choice Set  We are now in a position to define the notion of a feasible choice set. A claim that a given legal option is outside the feasible choice set is a claim about constitutional practice, and hence a claim about which possible worlds are practically accessible. Usually, a claim that a given legal option is infeasible will rest (either explicitly or implicitly) on a claim about human psychology, anthropology, economics, sociology, or political science.

For example, the claim that a constitutional amendment banning abortion is politically infeasible, if fully articulated, would rest on claims: (i) about the legal requirements for constitutional amendments, (ii) about beliefs and desires causally relevant to the motivations of constitutional actors such as congresspersons and state legislators, and (iii) about the beliefs and desires of citizens. Thus, the claim might be that, given the legal requirements, the motives of those whose assent is legally required for a constitutional amendment, and the attitudes of voters, a constitutional amendment banning abortion is impossible. In possible worlds talk, we might say that worlds in which such amendments become law are relatively remote from our own; in these worlds, political actors behave much differently or many citizens have different attitudes about abortion or the legal requirements for a constitutional amendment have been altered. This remoteness is the underlying reason for our judgment that such a constitutional amendment is outside the feasible choice set.

Legal options that exist only in possible worlds that are either historically or nomologically inaccessible are outside the feasible choice set in a very strong sense. They cannot come about in a future state of the actual world given the natural laws that govern this world. Legal options that exist in historically and nomologically accessible worlds may nonetheless be only remote possibilities: they may depend on changes in beliefs, desires, or institutions that depend on unlikely contingencies. When such possibilities are sufficiently remote, we may say they are outside the feasible choice set, but if we speak in this way, we are using "feasibility" in a sense that diverges from historical and nomological possibility.

Two Mistakes About Possibility

The Mistake of Reducing Possibility to Cost  Positive and normative law and economics provide powerful frameworks for thinking about the law and policy. Part of that power derives from a focus on costs and benefits. Frequently, we can understand and predict behavior by focusing on the expected costs and benefits of alternative actions. Sometimes, the action that is morally best is the action that accrues the greatest benefits or minimizes costs. If carried to an extreme, this focus on costs and benefits might lead to the conclusion that talk about possibility and feasibility can be reduced to talk about costs. We might come to believe that the sentence, “Outcome A is impossible,” can be reduced to, “Outcome A is too costly to be seriously considered.” Or “Choice B is not feasible,” might be equivalent to “Choice B is so costly that it should not be considered as an alternative.”

Possibility cannot be reduced to cost for several reasons. First, some kinds of impossibility are unrelated to cost (in even the broadest sense of that term). The number of Senators apportioned to each state cannot simultaneously be equal and proportionate to population; given unequal population size, this would be a logical impossibility. Second, the attribution of costs to options is dependent upon a prior notion of possibility. Thus, if we say that option A entails the accrual of cost n, that assertion depends on the prior assumption that a state of affairs in which option A is chosen, but cost n is not accrued is not a possible state. Third, even when costs play a causal role in establishing impossibility, agent relativity differentiates between costs as factors to be weighed in decisionmaking and costs that make certain outcomes practically impossible. For example, if respecting the freedom of speech is costly in cases involving advocacy of terrorism, the Supreme Court (as a relevant constitutional agent) might take that fact into account. And in some circumstances, high costs might lead the court to view a given constitutional rule as “infeasible.” But this is quite different from the court reaching the conclusion that compliance with a rule would be impossible, because the costs associated with compliance would be too large for the affected governmental entity to bear. In the first case, the costs are factors to be weighed in making the decision. In the second case, the costs are causal influences that determine which outcomes are possible from the point of view of the Court.

The Mistake of Reducing Possibility to Probability  Another tempting error is to equate possibility and probability. Possibility is normally understood as a binary function. An action, outcome, or event is either possible or impossible—once we specify the “sense of possibility” or, more technically, the accessibility relationships that define the relevant set of possible worlds. Probability, however, is a scalar: a given outcome may be “more or less likely” or, more formally, its probability may assume any real value from 0 to 1. The tempting mistake is to equate “possible” with “probability greater than zero” and “impossible” with “probability equal to zero.” Given this move, an even more serious error becomes tempting: one might then say that assertions of “impossibility” are actually assertions of “extreme improbability,” with the consequence that the concept of impossibility would turn out to be confused or mistaken. But the equation of possibility and probability is, in fact, based on conceptual confusion. The nature of the error is easiest to see in the case of logical possibility. It simply does not make sense to assert that it is merely improbable that the following two statements are both true: (1) this article was written entirely in the twenty-first century, and (2) this article was not written entirely in the twenty-first century. It is logically impossible that both statements are true, and the concept of improbability has no application to this kind of case. If someone were to assert the following: “The probability of both statements being true is zero,” we would understand that they were using probability in a figurative or metaphorical sense. There may be cases where “impossible” means “probability of zero,” but not all cases are like this. In some cases, talk of probabilities is simply inappropriate.

Avoiding Double Standards One last point before we conclude.  Arguments about legal possibility should avoid double standards. That is, if one argues against a legal alternative on the ground that it is outside the feasible choice set, then one is obligated to show that the preferred option or options are inside the set—on the basis of the same criteria and in light of available evidence. The possibility of a double standard can be illustrated by reference to a hypothetical dispute between advocates of constitutional originalism and Dworkin’s view of law as integrity. Originalists might claim that their approach is superior because it provides objective standards for correct constitutional interpretation. A Dworkinian might attempt to refute this claim by arguing actual judges are incapable of discerning the original public meaning of the Constitution; in the actual world, the argument might go, judges and justices lack both the historical chops and the capacity to set aside their own preferences. But if the Dworkinian (or quasi-Dworkinian) were then to appeal to Dworkin’s ideal judge, Hercules, when the feasibility of law as integrity was assessed, a double standard would have been imposed. In the actual world, the same judges who lack historical chops may lack Hercules’s capacity to construct the theory that best fits and justifies the law as a whole; in the actual world, the same biases that distort originalist judges could distort the method of law as integrity. Of course, we can easily imagine that the tables are turned and that it is the originalists who deploy a double standard.

Conclusion The concepts of "possibility" and "necessity" do a lot of work, but legal theorists frequently make arguments about feasibility without a theory.  This leads to confusion and creates the possibility of double standards.  The aim of this entry in the Legal Theory Lexicon has been to give you the tools to think clearly and consistently about legal possibilities.

References

John Divers, Possible Worlds (Rutledge 2002).

David Lewis, On the Plurality of Worlds (new ed. Wiley-Blackwell 2001).

Lawrence B. Solum, Constitutional Possibilities, 83 Indiana Law Journal 307 (2008).