When conviction of a given crime requires knowledge of some fact, courts commonly allow the defendant’s willful ignorance to satisfy this knowledge requirement. However, because most agree that willful ignorance is not actually a form of knowledge, the practice of allowing willful ignorance to substitute for knowledge calls out for justification. Why is it that some willfully ignorant defendants may be treated as if they possessed knowledge—even when they in fact did not? The traditional answer relies on the so-called “equal culpability thesis,” which provides that willful ignorance is just as culpable as knowing misconduct.

However, the equal culpability thesis itself is rarely given an explicit defense. The few arguments that have been offered in its favor fail. The present article aims to fill this void by offering a new account of what makes it the case that someone who commits the actus reus of a crime in a state of willful ignorance is at least as culpable as someone who does so knowingly. On the account defended here, willful ignorance involves the breach of a duty of reasonable investigation, and willfully ignorant defendants are as culpable as their knowing counterparts when they breach this duty in sufficiently serious ways.

Of course, equal culpability does not automatically entail identical legal consequences, and so this article concludes by investigating the legal significance of the equal culpability thesis (suitably restricted). In particular, the article argues that courts ought not give willful ignorance jury instructions unless a jury could reasonably infer from the trial evidence that the defendant’s willful ignorance made him at least as culpable as the analogous knowing criminal. In addition, a defense of the equal culpability thesis is of paramount importance to the legislative question of whether criminal statutes should be amended to explicitly permit willful ignorance to satisfy the knowledge element of various crimes. By providing a deeper understanding of the applicable principles of culpability, this article thus aims to pave the way for a more discerning and just application of the willful ignorance doctrine in the criminal law.


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