There is distinction between man and animal to justify man’s possession and use of the Earth’s resources explaining why humans have certain unique capabilities such as reason and language. The way Rousseau defines it is that because of this man is unlike any other animal due to the way man develops such as the way he looks or his physique. Through physical strength and the senses of natural man have been established there are more complicated functions to be discussed.
Metaphysical and moral man are what Rousseau intends to described as human intelligence and the higher functions of the brain. This is what exactly distinguishes man from animal. Suggesting that both are mechanical, the ability to act freely, allowing the choice to choose, varying their behaviour. Because of this, the faulty of perfectibility is suggested. Through different interpretations of this idea, it can be seen as a form of change or to have the ability to retain plasticity in order to mould into an individual’s environment. Without this quality, man can never be truly differentiated between man and animal causing Rousseau to argue that this is undeniably a great force.
Rousseau suggests that passions are a great driving force to reason and through this producing the needs in order to fulfil their desires. It is seen that reason and passion go against the basic philosophical ideas and it is also seen through Plato’s work as they fundamentally oppose each other. It is seen that reason can and should rule over passion or even passion ruling over reason. However, in Rousseau’s argument, he suggests passions as a strong emotion that entitles motivation and to reach beyond the possible, and from these emotions, it causes man to develop and act. The leap between passion to the development of reason creates the idea that this theory only works with the prior existence of passion before reason.