Numerical Arguments and Mens Rea

In his article “Mens Rea by the Numbers,” Yaffe connects what we have studied so far this semester to a current political debate. There was a bipartisan criminal justice reform bill on the table in 2020 that was ultimately voted down even though both parties backed it. One reason this bill was voted down is because of efforts to include mens rea reform in the bill. These reforms first called for a default mens rea provision — that knowledge of each material element be required for guilt. Second, the reforms called for a knowledge of illegality provision — that knowledge of the illegality of the conduct is necessary for guilt.

Typically when philosophers bring current political events into their scholarly work, I get a little concerned. However, Yaffe handles this political debate well. He even suggests how his philosophical argument undermines both sides of the aisle on this issue and presents a new way forward. Rather than further polarizing the current political climate, he presents a helpful alternative.

He argues that both parties relied on numerical arguments to determine if the mens rea reform should be included. Many republicans wanted the mens rea reform, because it would keep people without a malicious mens rea from being convicted, though some would be able to slip passed the suggested provision. However, many democrats wanted the mens rea reform as it would make it easier to convict corrupt businessmen of their crimes, though it also makes it more likely for people without a malicious mens rea to be convicted.

Yaffe enters the fray by arguing that these arguments from numbers are innapropriate. He claims, “there is a decisive and simple argument in favor of the default mens rea provision: we should not punish without mens rea” (Yaffe, 395). Thus, Yaffe argues in favor of the default mens rea provision without appealing to the numerical arguments popularly employed in the debate over this bill. Instead, his argument was, rightly, based on the claim that conduct without a malicious mens rea cannot justly be punished.