with whom Justice Marshall joins, concurring in part and dissenting in part.
I agree with the Court’s conclusion that the availability of prejudgment interest in a suit under the Federal Employers’ Liability Act (FELA), 35 Stat. 65, as amended, 45 U. S. C. §51 et seq., is governed by federal law, and that the state trial court therefore was not at liberty to supplement appel-lee’s judgment on the basis of Rule 238 of the Pennsylvania *343Rules of Civil Procedure. I also agree with the Court’s conclusion that the trial court erred in refusing to instruct the jury on present value pursuant to federal law. Accordingly, I join Parts I, II-A, and III of the Court’s opinion. Because the Court’s hasty decision that prejudgment interest is uniformly unavailable in FELA actions fails to follow the teaching of our prior cases and undermines the FELA’s system of compensation, I dissent from Part II-B.
I
Section 1 of the FELA, 45 U. S. C. §51, provides that a railroad “shall be liable in damages to any [employee] suffering injury . . . from the negligence” of the railroad or its employees. Enacted to ensure compensation for railroad workers injured by the negligence of their employers or of their fellow employees, the FELA uses broad language that, in turn, “has been construed even more broadly” by this Court, consistent with its assessment of congressional intent. Atchison, T. & S. F. R. Co. v. Buell, 480 U. S. 557, 561-562 (1987); see Kernan v. American Dredging Co., 355 U. S. 426, 432 (1958). This Court has “accepted [a] standard of liberal construction in order to accomplish” the “Act’s humanitarian purposes.” Urie v. Thompson, 337 U. S. 163, 180 (1949); Atchison, T. & S. F. R. Co. v. Buell, supra, at 562. In accord with these principles, appellee is entitled under the FELA to interest on the money awarded to him as damages for his economic losses, here lost earnings, between the time of his injury and the time of trial.1
*344A
Although the FELA allows recovery of “damages,” it does not specifically state that “damages” includes interest. Nonetheless, “in the absence of an unequivocal prohibition of interest . . . , this Court has fashioned rules which granted or denied interest on particular statutory obligations by an appraisal of the congressional purpose in imposing them and in the light of general principles deemed relevant by the Court.” Rodgers v. United States, 332 U. S. 371, 373 (1947). Plainly, the “congressional purpose” in providing a damages award under the FELA was to compensate a worker for his injury. Nothing in the legislative history or in our decisions suggests that this compensation was intended to be anything less than what was required to compensate him fully. The relevant “general principle” employed by this Court in interpreting the FELA is the provision of liberal recovery under flexible remedies. See Kernan v. American Dredging Co., 355 U. S., at 432 (“[I]t is also clear that Congress intended the creation of no static remedy, but one which would be developed and enlarged to meet changing conditions and changing concepts of industry’s duty toward its workers”). Together, purpose and principle indicate the allowance of interest in FELA cases.
To compensate an injured rail employee fully for income lost prior to trial, it is necessary to award not only the amount of the lost income, but also interest on that income for the time the employee did not have the use of it. “The interest foregone on lost income or on money spent for out-of-pocket expenses from the date of loss to the time of compensation is as much a part of making an injured party whole as is the calculation of her wage rate.” Wilson v. Burlington Northern R. Co., 803 F. 2d 563, 566 (CA10 1986) (concurring *345opinion), cert. denied, 480 U. S. 946 (1987). In recognition of the principle that an interest award may be necessary to provide full compensation, this Court, in other contexts, repeatedly has authorized prejudgment interest for economic injury when the purpose of the overall award is to make the plaintiff whole. See General Motors Corp. v. Devex Corp., 461 U. S. 648, 654-656 (1983) (patent infringement); Jacobs v. United States, 290 U. S. 13, 16-17 (1933) (eminent domain); Waite v. United States, 282 U. S. 508, 509 (1931) (patent infringement); Miller v. Robertson, 266 U. S. 243, 256-259 (1924) (contract). In short, it cannot be denied that an award of interest on pretrial economic losses in an FELA case is necessary to make the injured worker whole, and that making the worker whole is the purpose of the FELA.2 It would seem apparent, therefore, that, under our normal method of deciding such questions, a prejudgment interest award is appropriate in an FELA case.
B
In reaching the opposite conclusion, the Court relies principally on a common-law rule that barred prejudgment interest in suits for personal injury or wrongful death. Ante, at 337-338.3 From the combination of this common-law rule *346and the FELA’s silence on interest, the Court would discern a congressional intent to disallow interest awards entirely in FELA cases — an intent, in effect, to deny full compensation to workers covered by the FELA.4 Closer scrutiny of the development of interest and damages law, however, reveals the flaws in this facile analysis.
The common law’s hostility to interest awards usually is traced to the medieval view of interest as an evil thing. See D. Dobbs, Law of Remedies §3.5, p. 165 (1973); C. McCormick, Law of Damages §51 (1935). Before the time of Henry VIII, English common law prohibited the payment of interest even for the lending of money. 1 T. Sedgwick, Measure of Damages § 283 (9th ed. 1912). The abhorrence of all forms of interest gradually receded, so that, by the time of the FELA’s enactment, it was “almost universally held in this country that interest is in the proper case given as damages by the common law.” § 293; 1 T. Sedgwick, Measure of *347Damages § 293 (8th ed. 1891). Thus, to an authority writing in 1891, 17 years before the passage of the FELA, “[t]he gradual extension of the principles allowing interest as damages [was] clear.” §297.
To be sure, claims for interest often were summarily dismissed in personal injury and wrongful-death suits. See McCormick § 56, p. 224. It was, nonetheless, “the prevailing view [that] interest may be allowed in all actions of tort where the loss is pecuniary,” 1 T. Sedgwick, Measure of Damages §316, p. 630 (9th ed. 1912), and, even prior to the FELA, interest sometimes was allowed on economic losses that had resulted from personal injury. See Washington & Georgetown R. Co. v. Hickey, 12 App. D. C. 269, 275-276 (1898); Georgia R. & Banking Co. v. Garr, 57 Ga. 277, 280 (1876); see also Ell v. Northern Pacific R. Co., 1 N. D. 336, 353, 48 N. W. 222, 227 (1891) (pursuant to statute). However, because claims for lost earnings in personal injury suits frequently were joined with claims for noneconomic injury, such as pain and suffering, interest usually was not awarded. McCormick § 56, p. 224. Thus, the generalization about the unavailability of interest was criticized by Professor McCormick as “hasty and injudicious”: “It seems clearly desirable that the jury should at least be permitted, if not required, to add interest as compensation for delay in payment of those purely pecuniary losses which result from an injury to the person.” Ibid.
Against this background, one might conclude that, in mandating that railroads “shall be liable in damages,” Congress actually intended not to provide a blanket award of prejudgment interest on personal injury and wrongful-death awards under the FELA. Certainly, many FELA remedies, such as recovery for past pain and suffering and for future damages, are -widely viewed in the context of personal injury litigation as inappropriate objects for an interest award even today. See, e. g., Poleto v. Consolidated Rail Corporation, 826 F. 2d 1270, 1278, n. 14 (CA3 1987); Comment, Prejudg*348ment Interest: An Element of Damages Not To Be Overlooked, 8 Cumberland L. Rev. 521, 536-537 (1977). This is so because interest on these elements of damages is not necessary to full compensation.5 It should not be concluded, however, that Congress intended to deny interest on past economic losses, such as the lost wages that are a part of the recovery appellee seeks here. Therefore, the Court’s departure from our normal inquiry into the relation between an allowance of interest and Congress’ purpose in creating an obligation, and the Court’s indifference to the policy of liberal recovery under the FELA, are without justification.
C
The Court’s conclusion about the unavailability of interest in FELA actions is particularly curious coming, as it does, in a case which also involves the method of discounting an award of future damages to present value. Awarding prejudgment interest and discounting to present value are really two sides of the same coin. For precisely the same reason that “ ‘a given sum of money in hand is worth more than the like sum of money payable in the future,’” ante, at 339, quoting Chesapeake & Ohio R. Co. v. Kelly, 241 U. S. 485, 489 (1916), a given sum of money in hand is worth less than the like sum of money had it been paid in the past. It is hard to see how the Court can recognize that the meaning of “damages” under the FELA requires that future lost earnings be discounted to present value, but fail to recognize that the same term encompasses a mandate that past lost earnings be increased to present value, through the use of prejudgment *349interest. In effect, the Court thus only half-recognizes the principle that an FELA plaintiff is entitled to recover “ ‘the damages . . . [that] flow from the deprivation of . . . pecuniary benefits.’” Norfolk & Western R. Co. v. Liepelt, 444 U. S. 490, 493 (1980), quoting Michigan Central R. Co. v. Vreeland, 227 U. S. 59, 70 (1913).
Indeed, in previous discussions of present-value calculations, we have recognized the symmetry between discounting to present value and awarding prejudgment interest. In Jones & Laughlin Steel Corp. v. Pfeifer, 462 U. S. 523, 538, n. 22 (1983), the Court instructed:
“It is . . . more precise to discount the entire lost stream of earnings back to the date of injury — the moment from which earning capacity was impaired. The plaintiff may then be awarded interest on that discounted sum for the period between injury and judgment, in order to ensure that the award when invested will still be able to replicate the lost stream.”6
This Court has held that the present-value principles of Pfeifer apply in FELA actions. See St. Louis Southwestern R. Co. v. Dickerson, 470 U. S. 409, 411-412 (1985) (per curiam).
II
In sum, I conclude that prejudgment interest on past economic loss is available as part of the damages award in FELA *350cases. This reading of the statute comports with the congressional intent to provide liberal recovery under the FELA. Of course, by applying Rule 238 of the Pennsylvania Rules of Civil Procedure, the state trial court went further and allowed prejudgment interest on appellee’s general verdict, including interest on appellee’s damages for pain and suffering and future losses, which are not appropriate objects for a compensatory award of prejudgment interest. Because the trial court erred in its instruction on present value, however, ante, at 339-342, a new trial on damages will be necessary in any event. As part of appellee’s award at his new trial, I would allow interest on the past economic damages he has proved.
At the trial of this action, appellee sought recovery for, and the trial court instructed the jury on, four distinct elements of “damages” within the meaning of § 1 of the FELA: (i) appellee’s lost earnings from the time of his injury to the time of trial, (ii) appellee’s pain and suffering from the time of his injury to the time of trial, (iii) appellee’s future pain and suffering, and (iv) appellee’s future lost earnings. Tr. in GD 79-23765, Ct. Common Pleas, Allegheny Cty., pp. 694-695. Although the jury returned a single lump-sum verdict for appellee, a properly instructed jury could have returned a verdict that segregated past economic damages from noneconomic *344and future economic damages. In my view, the statute sanctions the award of prejudgment interest on only the first of these categories.
Of course, in not making the injured worker whole, a rule denying prejudgment interest provides a windfall to the defendant. It also creates an incentive for the employer to stall the litigation and postpone the judgment as long as possible. See General Motors Corp. v. Devex Corp., 461 U. S. 648, 656, n. 10 (1983). It seems unlikely that Congress intended such results to be part of its program of “liberal recovery” for workers.
The Court also relies on “Congress’ failure to disturb a consistent judicial interpretation” of the FELA denying prejudgment interest. Ante, at 338-339. However, “the doctrine of legislative acquiescence is at best only an auxiliary tool for use in interpreting ambiguous statutory provisions. . . . We do not expect Congress to make an affirmative move every time a lower court indulges in an erroneous interpretation.” Jones v. Liberty Glass Co., 332 U. S. 524, 533-534 (1947). See also Helvering v. Reynolds, 313 U. S. 428, 432 (1941). Moreover, the “consistent judicial interpretation” relied on here is particularly unpersuasive. “Few of the *346cases contain any extensive discussion of the subject. . . and . . . many of the recent cases simply note that the issue was settled in an older case that disposed of the point summarily.” Poleto v. Consolidated Rail Corporation, 826 F. 2d 1270, 1278 (CA3 1987). Indeed, a number of the most recent opinions have recognized the “excellent case” to be made for prejudgment interest under the FELA. Ibid. See also Wilson v. Burlington Northern R. Co., 803 F. 2d 563, 566-568 (CA10 1986) (concurring opinion), cert. denied, 480 U. S. 946 (1987); Garcia v. Burlington Northern R. Co., 597 F. Supp. 1304 (Colo. 1984), rev’d on other grounds, 818 F. 2d 713 (CA10 1987). Finally, of course, cases of this Court, by consistently giving the FELA a broad and flexible construction, have signaled the opposite result. See, e. g., Kernan v. American Dredging Co., 355 U. S. 426 (1958); Jamison v. Encarnacion, 281 U. S. 635 (1930).
I do not understand the Court to argue that the absence of any express reference to interest in the FELA is, by itself, probative. Certainly, such a contention could not succeed. First, as explained above, that approach is directly contrary to this Court’s settled technique for deciding questions of the availability of interest in the face of congressional silence. Second, the FELA’s express authorization of the recovery of “damages” may be read as providing for prejudgment interest. Indeed, as the Court properly recognizes: “Prejudgment interest... is part of the actual damages sought to be recovered.” Ante, at 335 (emphasis added).
Arguably, damages for pain and suffering are themselves not truly compensatory. See D. Dobbs, Law of Remedies § 8.1, pp. 548-560 (1973). Certainly, such awards are of a different character. They are inherently noneconomic and are established through the subjective discretion of the jury. Poleto v. Consolidated Rail Corporation, 826 P. 2d, at 1278, n. 14. Prejudgment interest on these speculative awards does not make up for the lost use of money and cannot be considered compensatory in any realistic sense.
In re Air Crash Disaster Near Chicago, Illinois, on May 25, 1979, 644 F. 2d 633 (CA7 1981), on which the Court in Pfeifer relied, stated the necessary relation between interest awards and discounting to present value even more plainly:
“[Even when] prejudgment interest [is rejected] as a separate element of damages, the measure of compensatory damages in wrongful death cases unquestionably does involve some form of interest in the determination of ‘present value.’ Prejudgment interest per se is not allowable [under Illinois law] as a separate element of a wrongful death damages award, but use of interest is implicit in the calculation of the present value of plaintiff’s pecuniary loss as of the date of trial.” 644 F. 2d, at 641.