In his book Two Concepts of Liberty, Isaiah Berlin formally framed the differences between these two perspectives as the distinction between two opposite concepts of liberty: positive liberty and negative liberty.
Dalam bukunya, Two Concepts of Liberty, Isaiah Berlin secara resmi merangka perbedaan antara dua prespektif ini sebagai perbedaan antara dua konsep kebebasan yang berlawanan: kebebasan positif dan kebebasan negatif.