Is it said: There is no riba (usury or interest) in paper currency because it is not weighed?

Question:
He says: Honorable Shaykh, may Allah grant you success. Since the operative cause in gold and silver is weight, do we say that there is no riba in paper currency because it is not weighed? This is the statement of the jurists that the operative cause is weight, but the correct view, and the one held by the meticulous scholars of knowledge, such as Shaykh al-Islam Ibn Taymiyyah,

Answer:
and the meticulous scholars, is that the operative cause in gold and silver is not weight, but rather their status as currency; that they are currency is the operative cause. Accordingly, paper currency is subject to riba because it is currency that the ruler has made to serve as a substitute for gold and silver. Even if we were to say that the operative cause in the two metals is weight, paper currency is a substitute for gold and silver, and a substitute has the ruling of the thing it substitutes, so riba applies to it in any case, whether we say the operative cause is weight or that the operative cause is currency, and the currency view is the stronger position. Yes.