Vaughan v Menlove (1837) 132 ER 490 (CP) is a leading English tort law case that first introduced the concept of the reasonable person in law. Facts As hay decomposes, heat is generated. In the absence of ventilation, the increased heat can cause a fire. The defendant built a hay rick (or haystack) near the boundary of his land which bordered the plaintiff's land. The defendant's hay rick had been built with a precautionary "chimney" to prevent the hay from spontaneously igniting, but it ignited anyway. He had been warned several times over a period of five weeks that the manner in which he built the hay rick was dangerous, but he said "he would chance it." Consequently, the hay ignited and spread to the plaintiff's land, burning down two of the plaintiff's cottages. Judgment Trial At trial the judge instructed the jury to consider whether the fire had been caused by gross negligence on the part of the defendant, and stated the defendant "was [duty] bound to proceed with such reasonable caution as a prudent man would have exercised under such circumstances." The jury found the defendant negligent. Appeal The defendant appealed the trial court's verdict, arguing the jury should have instead been instructed to consider "whether he acted bona fide to the best of his judgment; if he had, he ought not to be responsible for the misfortune of not possessing the highest order of intelligence." The court, composed of Tindal CJ, Park J and Vaughan J, rejected the defendant's argument, holding that the lower court's jury instructions were correct and therefore affirming the verdict. The court stated that to judge, The court indicated that although this was a case of first impression, the "man of ordinary prudence" standard was supported by a similar duty of care applied in cases of bailment, in which liability was imposed only for negligence relative to that standard. The court also viewed the "reasonable man" standard as supported by the long-settled principle that persons must use their property so as not to harm that of others (sic utere tuo ut alienum non laedas). Finally, the court held that the question of whether the defendant was liable because of negligence in violation of the reasonable person standard was a proper question for the jury ("The care taken by a prudent man has always been the rule laid down; and as to the supposed