While cause-in-fact doctrine addresses the question whether the accident would have happened even if the defendant had not breached his duty to take care, proximate cause doctrine fundamentally addresses the issue of foreseeability. In both areas, factual causation and proximate causation, the analysis begins with the plaintiff's identification of a specific breach theory – that is, some precaution that the defendant failed to take. After the breach theory is specified, factual causation analysis asks whether the accident would have happened even if the breach identified by the plaintiff had not occurred. In this sense, factual causation analysis works backward from the accident to the moment of the breach. In contrast, proximate causation analysis starts with identification of a specific breach and looks forward to determine whether the accident that occurred was foreseeable given the breach.

The language of foreseeability appears frequently in proximate causation cases, but the key concerns of the doctrine can be put into several categories. First, proximate cause doctrine is concerned with the predictability of the victim's injury, conditional on a particular instance of negligence. Second, proximate cause doctrine is concerned with the precision with which damages align with or target the most important source of the accident risk. Third, proximate cause doctrine attempts to avoid or reduce undesirable consequences of expansive and unpredictable tort liability. In short, proximate cause doctrine attempts to make tort liability operate on incentives a bit less like a mallet and more like a scalpel.

In carrying out this function, proximate cause doctrine appears to be shaped more by the general utilitarian policy reflected in the analysis of breach than by an effort to limit liability to the set of statistically predictable harms resulting from a given failure to take care. However, proximate cause analysis takes into consideration a broader set of consequences connected to holding the defendant liable than are considered in the breach phase of the negligence inquiry.

PROXIMATE CAUSE AS A LIMITATION ON THE SCOPE OF LIABILITY

Let's start with a comparison of factual and proximate causation doctrine in the context of the following Lightning Strike Hypothetical. Suppose an actor commits a negligent act that causes the victim to divert his path or delays the victim in his travel.