From the German "Aufheben".
As you take up an idea or concept, you'll be able to understand some aspect of it, which could be considered an abstraction of it, and this can be synthesized into some other action or observation. You may have negated some aspect of the original concept, and reduced it into a partial component, or even transformed the aspect of it into some new conception from which an abstraction can be more easily deduced, internalized, harnessed, and so forth.
In the other sense, to lift or take incurs the negation of having moved some object from its original place, but in doing so you are also engaging with that object, or carrying it across spacetime for a later point, preserving its potential for incorporation with that future event.
Absolute knowledge can only be attained after self-conscious recognition of another instance of self-consciousness. Believes that the entirety of reality is present to self-consciousness, and that this state is reached in 3 steps:
Dual interpretation: The dialectic interpreted as an internal process occurring in one person OR as an external process between two people.
This occurs because Hegel asserts "end to the antithesis of subject and object" - What occurs in the mind also occurs outside Objective and Subjective unified through sublation.
Two natural beings meet and find self consciousness in one another's independent existence. They are aware of one another's pre-reflective, exclusionary disposition which prioritizes itself.
Each being perceives itself as truly self-conscious through certainty of oneself as a thinking being. This constitutes an incomplete self-consciousness, failing to see the other as equivalent.
Interplay of manipulating the other, whereby they see themselves reflected in the other. This yields a form of narcissism.
The self loses itself when finding itself as the other, which is also sublation in the sense of having reduced the representation of the other to its own self.
When confronted with the other, the self cannot be immediately recognized. The other is like an ordinary object.
The fight, nearly to the death. If one dies, self consciousness is not achieved. This is an "abstract negation". Death is avoided by agreement and subordination to slavery.
One transformed into master as they do not perceive their identity as dependent on life, thus eliminating fear. The other is transformed into slave out of fear.
Recognition of the other gives each self-certainty required for self-consciousness. Relation of master/slave preserves the recognition of each other. In recognizing the other, one's own consciousness is made into an unessential object, but realization of this object constitutes certainty of self
This state is not sufficient to achieve full self-consciousness. Slave only recognizes pain of death. Master's self-consciousness is dependent on the slave for recognition.
Slave creates increasingly sophisticated products for master from nature due to creativity, and sees himself reflected in the products, thus causing him to realize that the world is created by his hands. The slave is no longer alienated from his own labour and achieves self-consciousness, while the master becomes dependent on the products created by the slave, resulting in his becoming a slave.