Abstract Part of the debate fueled by cryptocurrencies has revolved around the question of what we call money. This paper identifies two traditions in monetary theory that have tried to answer that question. On the one hand, the money or non-money view follows a strategy proposed by a version of philosophical essentialism , in which there is a set of defining characteristics of money that make it categorically different from other things used in transactions. On the other hand, the liquidity degree view emphasizes that the multiple objects that circulate as a means of payment differ in their degree of acceptability. Since there is no absolute standard of liquidity, a precise dividing line between money and non-money cannot be drawn. We challenge the money or non-money view , arguing that there is nothing in the nature of money that can be interpreted as a natural kind essence by which money can be categorically separated from non-money.