Cause in Fact (But-for)

But-for causation requires plaintiff’s injury would not have occurred without defendant’s conduct.

Related Causation & Damages rules

• Substantial Factor TestWhen multiple causes exist, defendant is liable if conduct was a substantial factor in harm.
• Alternative LiabilityWhen multiple negligent defendants and uncertainty about cause, burden shifts to defendants to disprove causation.
• Proximate CauseDefendant liable for harms that are foreseeable results of negligent conduct.
• Intervening CausesForeseeable intervening acts do not break causation; unforeseeable superseding causes do.
• Thin Skull RuleDefendant takes plaintiff as found and is liable for full extent of harm.
• Damages RequirementNegligence requires actual damages; nominal damages unavailable.
• Comparative NegligenceNegligence damages reduced by plaintiff’s percentage of fault.
• Contributory NegligenceContributory negligence is a complete bar unless last clear chance applies.

Part of Torts on Core Legal Rules — foundational MBE-tested principles with primary-source citations.