In this commentary, I suggest that it may be helpful to think about the formidable problem space that Westergaard's (2021) Linguistic Proximity Model seeks to address at the three levels of analysis that Marr (1982) famously proposed are needed to understand any complex cognitive system. I argue that at the computational level of analysis, where it appears the Linguistic Proximity Model is epistemiologically situated, the notion of copying grammatical representations is unproblematic, contrary to Westergaard's concerns.