The Age of Enlightenment emphasized reason over tradition in order to challenge religious views and promote knowledge of scientific thought. Reason is what differentiates humans from animals by allowing them to think about circumstances rationally rather than strictly by instinct. Jean-Jacques Rousseau embodies the Enlightenment ideals of introducing reason into everyday life in his book A Discourse on Inequality by stating that the creation and use of language by early humans shows how reason is used so to challenge ideas to imagine better solutions. This way of showing that early humans used reason is both extended and challenged in Mary Shelley's Frankenstein. This text also uses language as a way to use reason, but it does so in a way that shows the use of reason in a positive and negative light, supporting and contradicting the theory shown by Rousseau and that of the Enlightenment. Rousseau believes that in the beginning humans did not have or use innate reason but were only aware of instinct and basic feelings such as hunger, thirst and light. He states that “man's first feeling was that of his existence, his first concern was that of self-preservation” (Rousseau, 109). Primitive man, knowing of his existence, only knows what to do and how to survive thanks to his instinct which is innate in every living creature. Instinct tells the living creature to survive; that is, do everything necessary to preserve yourself. Primitive man spends his time thinking and doing only the things necessary for his survival, leaving no time to reflect on why they are doing what they are doing. This leads to a stagnant society devoid of reasons/thoughts that question one's own motivations and those of others. Shelley extends and supports… half of the paper… then points out that through the expansion of language there is a greater need and use of reason among human beings. Shelley challenges the Enlightenment idea of ​​reason by pointing out that even if people use reason with a clear mindset, that is, a mindset not overly focused on a single goal, other people can manipulate the use of reason to achieve the goal they desire. want without this being a reasonable goal. This complicates the traditional view of using reason to know when to trust others and when not to trust others. If a person is perfectly reasonable with a clear mindset and thinks that something someone else tells or shows them is a reasonable thing, they may still come to the wrong conclusion if they receive false information. This raises the fundamental question: even if we are reasonable people, can we really trust anything or anyone?