Rousseau and Mills, on progressive beings

Judging from what they have to say in On Liberty and the Second Discourse, in what sense do
Mill and Rousseau consider us to be “progressive beings” and what implications do they think
this has for human freedom?
Previously, Mills indicates the way in which humans are progressive. According to him the ideal
form of progressiveness can be found in humans being able to “regard utility as the ultimate
appeal on all ethical questions” (Mills, pg 12). Thereby having utility be the judge of our actions,
thus guaranteeing our personal happiness in terms of our individual actions