Underlying History of the Case

The underlying history underscores the openness of the legal question and the consequent uncertainty as to the answer. When Congress enacted the Federal Employers’ Liability Act (FELA) in 1908, 45 U. S. C. §§51–60, the kinds of injury that it primarily had in mind were those resulting directly from physical accidents, such as railway collisions and entanglement with machinery. See Consolidated Rail Corporation v. Gottshall, 512 U. S. 532, 542 (1994). And (where negligent conduct was at issue) the Restatement nearest in time to FELA’s enactment (and therefore presumably likely to be more reflective of the background rules that FELA then assumed, cf. Id., at 554– 555) limited recovery for related emotional distress to concrete harm resulting from that distress. Restatement of Torts §456 (1934) (hereinafter Restatement). In particular, this earlier Restatement restricted recovery to “physical harm resulting . . . from fright or shock or other similar and immediate emotional disturbance” substantially caused by the underlying injury or negligent conduct. Ibid.