“Causal potency” and contributory negligence
A lot could be said on causation as it relates to contributory negligence, but in this post I will restrict myself to commenting briefly on two fairly recent cases.
The first is the Supreme Court’s decision in Jackson v Murray  UKSC 5. The facts were (in short) that on a winter’s evening, a thirteen-year-old girl was severely injured when, stepping out from behind a minibus to cross a country road, she was struck by a car. The driver of the car, who had seen the minibus but had not contemplated anyone trying to alight from it and immediately cross the road, was driving too fast. He failed properly to observe the road conditions, and had not seen the girl when she stepped out. Had he been driving at a reasonable speed, and had he been properly observing the road conditions, he would not have hit the girl.
The Lord Ordinary found that the accident was the result of the driver’s negligence, but also that the girl had been contributorily negligent. He assessed her contributory negligence at 90%, and reduced the damages to be awarded accordingly. On appeal to the Inner House, the appeal bench reduced the level of contributory negligence to 70%. The girl further appealed to the Supreme Court.
The Justices of the Supreme Court held (by a 3:2 majority) that, in the absence of some identifiable error, only a difference of view regarding the apportionment of responsibility which exceeded the ambit of reasonable disagreement would warrant the conclusion that a lower court had erred in apportioning the quantum of contributory negligence. On the facts of this case, the majority took the view that there was no satisfactory explanation for the view of the Inner House that the major share of responsibility for the girl’s injuries was properly attributable to her. The defender’s conduct played at least an equal role in causing the injuries, and was at least equally blameworthy. The court below having thus erred in its decision, the girl’s appeal was allowed and a figure of 50% reduction in damages on account of contributory negligence was applied to the award.
Is the reasoning underlying the decision right? The Law Reform (Contributory Negligence) Act 1945 governs the allocation of contributory negligence in Scottish delictual claims as well as tort claims arising in other parts of the UK. The principal provision of the Act (sec 1 (1)) states that
‘Where any person suffers damage as the result partly of his own fault and partly of the fault of any other person or persons, a claim in respect of that damage shall not be defeated by reason of the fault of the person suffering the damage, but the damages recoverable in respect thereof shall be reduced to such extent as the court thinks just and equitable having regard to the claimant’s share in the responsibility for the damage.’
Though laudable in its aim, this provision suffers from an inherent vagueness: the stipulation that the reduction in damages to be made for contributory negligence is to be such as ‘the court thinks just and equitable’ given the pursuer’s ‘share in the responsibility’ for an injury leaves it unclear on what basis such responsibility is to be judged. Greater responsibility might conceivably be merited for claimant conduct which is more blameworthy than the conduct of the defender; or a court could, for some other reason, hold that one of the causes-in-fact of the injury ought to attract a greater share of responsibility-this is often masked in causal language, by saying that one of the causes is ‘more potent’ than the other, but I think this causal language obscures what is going on. Given the vagueness of the statutory language, the potential for conflicting judicial approaches is evident.
In Davies v Swan Motor Co (Swansea) Ltd  2 KB 291, Denning LJ opined that causation was the ‘decisive factor’ in the exercise. But that view has not been popular in more recent decisions, which seem to proceed from the approach that blameworthiness and so-called ‘causal potency’ are equally important factors. The court in Jackson refers to the appropriateness of considering both factors: so, Lord Reed states that the defender’s conduct ‘played at least an equal role to that of the pursuer in causing the damage [i.e. was as ‘causally potent’, as it might alternatively have been put] and was at least as blameworthy’ (emphasis added).
Lord Reed addressed the issue of alleged causal potency in some of his remarks. He contrasts cases where a pedestrian may walk out directly in front of a car (in the case before the court, the girl had stepped out some distance ahead of the car), saying that in such cases the pedestrian’s conduct is the ‘more direct and immediate cause of the damage’, interrupting a situation in which an accident would not otherwise have happened. But here we see a difficulty with using causal language to try and solve the problem: the language of ‘direct’ and ‘immediate’ cause adopts the traditional language of so-called legal causation (i.e. determining whether causes-in-fact are sufficiently important to factor in the attribution of responsibility for harmful outcomes). The use of such traditional legal causal language has been forcefully argued in recent years (principally by Jane Stapleton, and in much less impressive style by myself) to mask the true nature of what is going on, and to be suggestive of matters of scientifically observable causal effect. But it is not about that; it is rather about what Stapleton has called the ‘scope of liability for consequences’, which is not a causal question. In this case, each of the driver’s and child’s behaviour was a ‘but for’ cause of the accident; using the language of ‘direct and immediate’ cause to describe either is obfuscatory. What is really going is that the court thinks a driver is in a position of greater power on the roads, and so his/her behaviour ought to attract a great share of responsibility for the accident. Indeed, Lord Reed is suggesting as much at para 26, when he refers to Eagle v Chambers  EWCA Civ 1107,  RTR 115, in which he says ‘[t]he court had consistently imposed a high burden upon the drivers of cars, to reflect the potentially dangerous nature of driving‘ (emphasis added). Putting it that way shows that we aren’t dealing with the supposed ‘potency’ or ‘directness’ of the cause, whatever such phrases are supposed to mean; or about a cause’s ‘immediacy’, an equally unhelpful idea given that the conduct of both parties in Jackson coincided temporally, so neither can meaningfully be said to have been more ‘immediate’. The real reason is, as Lord Reed is I think suggesting in para 26, that a policy choice has been made to view driving as more dangerous than crossing the road, given the power in the hands of a driver, and thus to hold that it is appropriate that the driver is responsible for a greater share of liability for the injuries.
That is what should have been emphasised in this case as the rationale for the apportionment. If the Supreme Court is still wedded to the unhelpful language of legal causation, then I don’t think we are going to get any nearer to understanding what is really going on in decisions like this.
Let me mention a second case, a Scottish Outer House road accident case from March 2017, in which I think the judgment suffers not only from flawed causal reasoning but also, as a result, is wrong in the decision it reaches. The case is Bowes v Highland Council  CSOH 53, 2017 SLT 749, in which the driver of a pickup truck was killed when his vehicle swerved as it approached a bridge, crashing into and through a weakened parapet on the bridge, and falling into a river. The Lord Ordinary (Lord Mulholland), reviewing previous Scottish authorities on the issue, felt obliged to follow the law applied in those authorities, viz that a council owes road users a common law duty of care for failures to remedy hazards caused by the state of the roads (and, by extension, road bridges). The fact that (says Lord Mulholland) English law does not recognise a duty of that scope was thought by the court to be irrelevant. The court held the Council liable for the driver’s death on account of its failure properly to maintain the parapet.
So, the case is interesting from a duty of care point of view. But for our present purposes, the especially interesting issue is the fact that, although the evidence showed that the deceased had been driving carelessly at the time of the accident (i.e. he had been negligent ), this was held to be irrelevant. Why? Because, said the judge (and I quote the entirety of the passage in which the issue was considered):
‘As the deceased did not contribute in any way to the defective parapet and would not have lost his life had the parapet been operating as designed, in fact he would only have sustained minor injuries or none at all, I do not regard the deceased’s negligent driving as having contributed in any significant way to causing the harm. I am consequently of the opinion that there is no basis for any finding of contributory negligence on the part of the deceased and I therefore reject the defender’s case of contributory negligence.’ [para 34]
This reasoning does not I think stand up to close analysis. The fact that, absent the council’s negligence, the deceased would not have died, is an incomplete and insufficient reason for excluding his negligence as a cause of the accident. One could equally make an alternative counterfactual statement, as follows: had the driver not been driving negligently, his vehicle would not have swerved, left the road, and struck the parapet, and he would not have plunged to his death. If one makes that counterfactual statement, then (on the court’s logic) one would end up by saying that it was the driver who was solely responsible for the harm suffered, and that any alleged negligence on the council’s part was irrelevant. Of course, the correct causal analysis is that each of the driver’s negligence and the Council’s negligence were necessary conditions for the outcome, and that a set of causes minimally sufficient for that outcome is one which includes the faulty conduct of each. If therefore one wants to exclude the driver from responsibility, the reasoning for doing so cannot be causal: there would need to be some other reason for justifying such a conclusion (if indeed, that really is the correct conclusion). That reason could perhaps be that the council’s duty is a socially more important one, and that in order to emphasise such importance one needs to exclude the driver’s negligence. I’m not however convinced by that, however, and I think there should have been some discounting for contributory negligence in this case, in order to emphasise that the duty on drivers to drive carefully is also a significant and important one (as we saw in the Jackson case), given the risk that badly driven vehicles pose to their occupants and to other road users. Bowes is a case where I think misguided application of causal reasoning hinders not only the proper analysis of the legal issues but also the correct outcome.
These two recent cases suggest that inappropriate adoption of a supposedly causal analysis is hindering proper application of the principle of contributory negligence. If something is to change, then we need to get away from the language of causal potency and immediacy which is inherent in traditional legal causation thinking.