The Problem of Indeterminate Causation

• Author: Jamie Cassels - Craig Jones
• Pages: 203-248

4. The Problem of

Indeterminate Causation

A. CAUSATION PROBLEMS IN LARGE-SCALE WRONGS

In mass tort cases, especially those involving large numbers of persons

who have been exposed through negligence to toxic substances that cause

adverse health effects through non-observable modes of causation (often

called “toxic torts”), the traditional rules of law and procedure often appear

both inefficient and unfair. Modes of procedure and evidence that require

proof and assessment on a particularistic, individual-by-individual basis do

not easily accommodate claims based on non-traumatic, gradual, or cumu-

lative harms.

Much has been written recently on the problem of causation, since the

conceptual framework of nineteenth-century tort law has had to evolve to

meet claims for injury compensation for harms that are more widespread

and causally complex. The variety of products, processes, and activities that

can cause injury have vastly expanded during that time. Modes of mass

production and distribution ensure that the potential consequences of

error are more widely felt and scientific understandings of causal relation-

ships have vastly expanded (and complicated) our understanding of the

links between products, activities and environments, and harms to human

health.

Tort scholars and courts have debated doctrinal innovations such as

onus-shifting and presumptions and procedural innovations such as sci-

203

ence panels1and the aggregation of claims through the aggressive use of

class action suits.2Certainly, these methods have potential to ease some of

the problems of particularistic proof. But dealing with large-scale claims on

a probabilistic basis may require more than procedural innovation and

advanced methods of proof of causation. In fact, it may require that we re-

examine the necessity of establishing precise causal connections between

plaintiff and defendant at all.

In the 1970s and early 1980s, Posner,3Calabresi,4and others5consid-

ered the question of causation in law in terms of economic efficiency, lay-

ing the groundwork for many of the “instrumentalist,” “functionalist,” or

“utilitarian” proposals that followed. The late 1980s led to further analyses

by Fleming,6Moore,7Brennan,8Wright,9and Ginsberg and Weiss,10 all of

whom canvassed possible solutions to what Fleming called “the problem of

the indeterminate defendant.”11 Proposals for reform that included the

imposition of liability on the basis of risk — rather than harm — were

THE LAW OF LARGE-SCALE CLAIMS204

1 T.A. Brennan, “Causal Chains and Statistical Links: The Role of Scientific Uncertainty

in Hazardous-Substance Litigation” (1987–88) 73 Cornell L. Rev. 469.

2 Harvard’s David Rosenberg has been perhaps the most outspoken champion of the

latter approach, and we have discussed procedural options elsewhere: See D. Rosen-

berg, “Class Actions for Mass Torts: Doing Individual Justice by Collective Means”

(1987) 62 Ind. L.J. 561; D. Rosenberg, “Of End Games and Openings in Mass Tort

Cases: Lessons from a Special Master” (1989) 69 B.U. L. Rev. 695; D. Rosenberg,

“Individual Justice and Collectivizing Risk-Based Claims in Mass-Exposure Cases

(1996) 71 N.Y.U. L. Rev. 210; D. Rosenberg, “Mandatory-Litigation Class Action: The

Only Option for Mass Tort Cases” (2001) 115 Harvard L. Rev. 831. See also C. Jones,

Theory of Class Actions (Toronto: Irwin Law, 2002); J. Cassels, The Uncertain Promise of

Law: Lessons from Bhopal (Toronto: University of Toronto Press, 1993) at 75–95.

3 R.A. Posner,“A Theory of Negligence” (1972) 1 J. Legal. Stud. 29; R.A. Posner, “The Con-

cept of Corrective Justice in Recent Theories of Tort Law” (1981) 10 J. Legal Stud. 187.

4 G. Calabresi, “Concerning Cause and the Law of Torts” (1975–76) 43 U. Chi. L. Rev. 69.

5 See the discussion of “actuarial causation” in J.D. Fraser & D.R. Horwarth, “More

Concern for Cause” (1984) 4 Leg. St. 131. The initial role of the legal economists in the

causation debate is well summarized in H.L.A. Hart & T. Honoré, Causation in the

Law, 2d ed. (London: Oxford, 1985) at 67–81.

6 J.G. Fleming, “Probabilistic Causation in Tort Law” (1989) 68 Can. Bar. Rev. 661.

7 M.S. Moore, “Thomson’s Preliminaries About Causation and Rights” (1987) 63 Chi.-

Kent L. Rev. 497.

8 Brennan, supra note 1.

9 R.M. Wright, “Causation in Tort Law” (1985) 73 Calif. L. Rev. 1735.

10 Ginsberg & Weiss, “Common Law Liability for Toxic Torts: A Phantom Remedy”

(1981) 9 Hofstra L. Rev. 859.

11 Fleming, supra note 6; McLachlin, J., “Negligence Law — Proving the Connection” in

Mullany & Linden, eds., Torts Tomorrow, A Tribute to John Fleming (Sydney: L.B.C

Information Services, 1998) at 18.

greeted with deep suspicion by those who saw tort law not from a function-

al but from a “corrective justice” point of view, such as Epstein12 and Wein-

rib,13 and the question became a significant focus of the debate between the

economic analysts of law and those purporting an independent, normative,

or moral role for tort.14 Despite the differences in approach, most who con-

fronted the issue seemed to agree that causal uncertainty presents central

questions for philosophers and lawyers alike.15

Mass claims present both unique problems of causation and also

unique opportunities for dealing with causal indeterminacy in a principled

and effective way. Ideas of “probabilistic causation,” inherently difficult in

individual cases, begin to make sense when harm is viewed in aggregate

populations. Indeed, it is in mass tort claims where the most interesting

innovations in causation analysis can be expected.

B. THE INADEQUACY OF THE “BUT FOR” TEST

There are both factual and legal elements to the traditional analysis of cau-

sation in tort and in negligence in particular. Generally, one must demon-

strate causation in fact according to the “but for” test, asking whether the

plaintiff would have escaped loss but for the defendant’s conduct. Then the

question of proximate cause arises — whether the link in question is close

enough to merit the imposition of legal responsibility.16 This might be char-

The Problem of Indeterminate Causation 205

12 Epstein’s views were set out in detail in R. Epstein, “A Theory of Strict Liability”(1973)

2 J. Legal. Stud. 151; R. Epstein, “Causation — In Context: An Afterword” (1987) 63

Chi.-Kent L. Rev. 653.

13 E.J. Weinrib, “Causation and Wrongdoing” (1987) 63 Chi.-Kent L. Rev. 407.

14 The original debate is captured in R.A. Posner, “Epstein’s Tort Theory: A Critique”

(1979) 8 J. Legal Stud. 457.

15 M. Kelman, “The Necessary Myth of Objective Causation Judgments in Liberal Politi-

cal Theory” (1987) U. Chi.-Kent L. Rev. 579 at 580 “[T]he two liberal theories of the

state dominating mainstream legal thought, libertarianism and efficiency-orientation,

both rely to an alarming extent on the false premise that causal uncertainty is a

peripheral issue.”

16 Horsley v. MacLaren, [1972] S.C.R. 441. The question of “remoteness” and the related

idea of “foreseeably” is most famously discussed in the case of Palsgraf v. Long Island

Railroad Company, 248 N.Y. 339 (N.Y.A.D. 1928), rearg. den. 249 N.Y. 511 (N.Y. 1928)

[hereinafter Palsgraf], where an extraordinary unlikely igniting of fireworks at a train sta-

tion led to a bystander’s injury from falling scales. The Palsgraf rules were modified in

Derdiarian v. Felix Contracting Corp., 51 N.Y.2d 308 at 315 (Ct. App. 1980) to break the

“causal nexus” where “the intervening act is extraordinary under the circumstances, not

foreseeable in the normal course of events, or independent of or far removed from the

defendant’s conduct.”