Letters Upon The Aesthetic Education of Man, 1794

Friedrich Schiller’s On the Aesthetic Education of Man, in a Series of Letters is a philosophical piece of the source of art and beauty. The Letters seeks to articulate how aesthetic education is a way to which political freedom can be achieved when a person can be a fully man and a fully citizen.
For the first enquiry of the five letters to the reader was describing of how art and beauty are related to human freedom. Aesthetic allows the individual to exist beyond the inner and outer constraint. It enables the individual to experience physical and spiritual freedom.
In his opinion, the nature of moral instinct has given to man in order to serve as a guide and teacher until his enlightened intelligence gives him maturity. It can be concluded as a human’s being emotions have been educated by reason.
In Schiller's aesthetic philosophy, the human’s nature is divided into two. The human self (or Person) is that which persists, and its determining condition is that which changes. While the human self and its condition are distinct in finite being, but are united as an absolute being.
He also stated that time is determined by the unchanging self. Every human being is a Person who is situated in a particular situation. The original Intelligence within the Person is endless, but the Condition in which the Person finds himself or herself is determined by time. Thus, the succession of a Person’s perceptions in time leads to a consciousness of the phenomenon which is a self awareness.
Schiller asserts that human beings, as finite beings, must thus confront not only the task of trying to bring the necessity within themselves to reality, but the task of trying to subject the reality outside of themselves to the law of necessity. These two important and a challenging tasks  are determined by opposing forces in human nature: the sensual drive, and the rational drive. While the sensual drive is toward physical reality, the rational drive is toward formal reality.
Schiller also asserts that Person and Condition are reciprocally related realms of being, in that the more autonomy or self-determining activity is transferred to the Person, the less that the Person is subject to changing forces in the world. The more a Person is determine to change the forces in the world, the less autonomy or self-determining activity is transferred to the Person. Aesthetic activity is derived from a unity of Person and Condition, in that there must be a reality belonging to the Person if he or she has self-determining activity, and there must also be a reality belonging to the world if the Person must be situated in a Condition.
According to Schiller, aesthetic education can produce not only an increased level of awareness or receptivity to the world but can also produce an increased intensity in the determining activity of the intellect. The aesthetic impulse, or "play drive," can thus combine passive and active forces, which can produce a unity of feeling and reason.
If intensity is transferred from the active function of the intellect to the passive function of sensation, then the receptive faculty of sensation may predominate over the determining activity of the intellect. If intensity is transferred from the passive function of sensation to the active function of the intellect, then the determining activity of the intellect may predominate over the receptive faculty of sensation. Thus, the aesthetic ideal is achieved by an interaction of passive and active forces, producing a balance between feeling and reason.
While the sensual drive exerts a physical constraint, the rational drive exerts a moral constraint. While the exclusion of freedom from the function of the sensual drive implies physical necessity, the passivity from the function of the rational drive implies moral necessity.
The goal of the sensual drive is physical reality, while the goal of the rational drive is formal reality. The aesthetic ideal of beauty is thus defined by a unity of physical and formal reality.
Schiller asserts that beauty is an aesthetic unity of thought and feeling, of contemplation and sensation, of reason and intuition, of activity and passivity, of form and matter. The attainment of this unity enables human nature to be realized and fulfilled. Beauty (or aesthetic unity) may lead to truth (or logical unity). However, when truth is perceived, feeling may follow thought, or thought may follow feeling.When beauty is perceived, thought is unified with feeling.
According to Schiller, freedom is attained when the sensual drive and rational drive are fully integrated, and when the individual can allow both drives to be fully expressed, without being constrained by them. Thus, the state of true aesthetic freedom is achieved by a process of mediation between a passive state of feeling and an active state of thinking.