It’s time to re-think how to use the ‘but-for’ test

Richard Halpern of Gluckstein Lawyers discusses the proper use of the counterfactual question

This article was produced in partnership with Gluckstein Lawyers

By Julius Melnitzer | August 23, 2023

A veteran member of the plaintiff’s medical negligence bar says it’s time for change in how we think about causation in tort, by clarifying the traditional ‘but-for’ test based on its ‘counterfactual’ foundation, while dismissing, once and for all, any notion that alternative tests exist in tort for finding causation.

“The traditional test for causation, the ‘but-for’ test, which asks what the outcome would have been had the wrongful act not occurred, is a ‘counterfactual’ question that can be too narrow and too limiting if it continues to be invoked as a test of ‘strong necessity’ only,” says Richard Halpern, senior counsel in the Toronto office of Gluckstein Personal Injury Lawyers, whose six Ontario locations serve clients throughout Canada. “The perception that but-for is ‘unworkable’ in cases involving multiple causes is misguided.  The problem is with how we pose the causal question.”

By way of illustration, Halpern, who has detailed his views in a paper entitled Causation and the But-For Counterfactual: Vanquishing Material Contribution to Risk, published in the Advocates’ Quarterly, posits the classical case of three small fires that have combined to destroy a plaintiff’s property. Each was not strong enough on its own to cause the damage, but became strong enough when the fires merged.

“Let’s assume, however, that only the strength of two fires was required to cause the harm. If you apply the but-for test to any one of the three fires, as the causal question is commonly posed, you risk finding that none of the fires could be said to have caused the harm. But it can’t be true that none of the fires destroyed the plaintiff’s property. Therefore, either the test is deficient, or we are asking the wrong question. The latter is the case.”

As well, a properly formulated causal test, according to Halpern, must be . . . MORE

Julius Melnitzer is a Toronto-based legal affairs writer, ghostwriter, writing coach and media trainer. Readers can reach him at [email protected] or


Confusion continues about causation test in medical malpractice cases

Ontario Superior Court acknowledges the risks and obstacles facing the medical malpractice bar

Social Media Auto Publish Powered By :