What does 'take your victim as you find him' doctrine for causation in English tort law?

The “take your victim as you find him” doctrine for causation in English tort law is a principle that states that a defendant should be held liable for the full extent of the plaintiff’s damages, even if the plaintiff’s pre-existing condition or disability made them more susceptible to injury. This doctrine holds that a defendant should be held responsible for all of the damages that they caused, regardless of any pre-existing conditions that the plaintiff may have.