The Enlightenment was an 18th century philosophical movement in Western Europe. 

It is a movement dedicated to the pursuit of truth as empirically discoverable. Enlightenment thinkers believe that by using the power of Reason and observation, individuals can arrive at the truth and progress towards perfection.

The Enlightenment conceives the world as mechanistic and analyzes it piece by piece, trying to rationally identify and replace the parts that are not progressive or functioning with the belief that by fixing these parts a better society can be created. Contrary to previous thought, they see humans as capable of critically examining the self and other aspects of humanity.  They believe that intellectual progress was the basis of the journey towards the general progress of humankind. By scientifically studying the nature of man and the environment in which he lives, humans can direct their focus to progress towards perfection.

Enlightenment thinkers believe that there exists certain laws of nature that govern them, and by understanding these laws, reason can be deduced as a collection of facts. It is the unity of reason and observation that makes progress and the attainment of truth possible. The philosophes admire Newton, an observer who used the scientific method to infer results. Newton believed that facts are discovered through observation rather than abstract reasoning and noticed that these facts show patterns and relationships. The Enlightenment is therefore a shift from a religious to a scientific mindset. Man can form ideas and understand the world around him through perception, the senses and experience, for knowledge exists in its immediacy.

Many social theorist such as Kant and Michel Foucault critique the empirical epistemology of the Enlightenment.

In Kant's essay What is Enlightenment? Kant argues that the mind is never able to fully perceive objective reality. In Kant’s perspective, the mind always filters its perception of reality and therefore interprets it subjectively. Kant uses the terms noumena and phenomena to describe this process. Noumena are the material things in the world that exist external from the individual while phenomena are things as we perceive them. Kant argues that we can only perceive the noumena in a phenomenal form.

Another reason that Kant is critical of the empiricism of the Enlightenment is because he thinks it is important to recognize the limits of empiricism. According to Kant, there is knowledge that exists outside of empirical knowledge that is measured through other means than experiencing the external world. To illustrate this point, Kant discusses a priori categories, which exist in the mind and are separate from the “noumenal” world. Time and space both fall into these categories. The importance of a priori categories is that they are ideas rather than facts. Ideas, such as the mind’s construction of time, exist outside of the realm of empiricism and therefore cannot be measured using the epistemology of the Enlightenment.