What is negligence under the law?

Article 2176 of the New Civil Code prescribes a civil liability for damages caused by a person's act or omission constituting fault or negligence. It states:
Article 2176. Whoever by act or omission causes damage to another, there being fault or negligence, is obliged to pay for the damage done. Such fault or negligence, if there was no pre-existing contractual relation between the parties, is called quasi-delict and is governed by the provisions of this chapter.
In Layugan v. Intermediate Appellate Court,[1] negligence was defined as the omission to do something which a reasonable man, guided by considerations which ordinarily regulate the conduct of human affairs, would do, or the doing of something which a prudent and reasonable man would not do. It is the failure to observe for the protection of the interests of another person, that degree of care, precaution, and vigilance which the circumstances justly demand, whereby such other person suffers injury.[2]

To determine the existence of negligence, the time-honored test was: Did the defendant in doing the alleged negligent act use that reasonable care and caution which an ordinarily prudent person would have used in the same situation? If not, then he is guilty of negligence. The law here in effect adopts the standard supposed to be supplied by the imaginary conduct of the discreet paterfamilias of the Roman law. The existence of negligence in a given case is not determined by reference to the personal judgment of the actor in the situation before him. The law considers what would be reckless, blameworthy, or negligent in the man of ordinary intelligence and prudence and determines liability by that.[3]

[1] 249 Phil. 363 (1988).

[2] Id. at 373, citing Blacks Law Dictionary, Fifth Edition, 930; Cooley on Torts, Fourth Edition, Vol. 3, 265.

[3] Picart v. Smith, 37 Phil. 809, 813 (1918).