Rousseau Equality

Rousseau, your claims on the state of nature are questionable. You first claim that people equal in nature and thus are in a better state in nature. Yet, you then state that nature makes people more physically apt and that only the strong can survive. This would imply that a form of inequality, a natural prejudice would form against those not physically capable. Thus, you contradict yourself by stating that nature is equal and then imply a form of inequality in nature. In addition, it is important to raise the question: why do we even need a social contract in the first place? At some point in time in order for mankind to survive, they have to enter into a civilization. In order to for people to retain their natural equality, according to you,