Opinion of the Court
In the earlier precedent duty was imposed on defendants by voluntary contract via privity as in the English case of Winterbottom v. Wright, 152 Eng. Rep. 402, 403 (Ex. 1842) (denying injured man's suit against manufacturer because the judge found no privity between the defendant carriage maker and the injured plaintiff). This case brought products injuries into the modern tort law theory of a duty that all citizens owe each other by virtue of a defendant's relationship to the plaintiff. This is the precursor rule for products liability).

According to Professors John Goldberg of Vanderbilt University Law School and Benjamin Zipursky of Fordham Law (The Moral of MacPherson, 146 U. Pa. L. Rev. 1733 (1998)) by holding that the defendant manufacturer owed a duty of care to the ultimate purchaser despite the absence of privity - it didn't remove duty of care from the law of torts but re-affirmed duty. Zipursky and Goldberg argue that scholars like William Prosser misconstrued Judge Cardozo into an economist who only cared about efficiency in the tort law in the spirit of Judge Guido Calabresi's book the Cost of Accidents.