The mathematics are distinguished by a particular privilege, that is, in the course of ages, they may always advance and can never recede.

Gibbon contrasts mathematics with fields whose achievements can be forgotten, overturned, or rendered obsolete by changing tastes, politics, or new evidence. In his view, mathematical knowledge is cumulative: once a theorem is proved or a method established, later generations can build on it without needing to “unlearn” it. The “privilege” is thus mathematics’ unusual immunity to historical decay—its results remain valid across time and place, allowing steady progress. Implicitly, the remark also flatters the Enlightenment ideal of secure, demonstrable knowledge, suggesting that mathematics offers a model of certainty and durable advancement that other branches of learning rarely match.