Spinoza pointed out that all affirmation involves negation (to claim a thing “is” something, is to simultaneously claim that it “is not” many other things). Hegel added the converse; all negation involves affirmation (to claim a thing “is not” something is to claim it is the inverse of that negation).
Spinoza, Hegel, Affirmation, and Negation
To this, I add: Spinoza’s assertion and Hegel’s assertion together suggest a new level of interdependence. Determining or defining anything involves negations and affirmations that are interdependent with one another. What I am and what I am not are interdependent. What each thing is and is not are interdependent. All knowledge claims involve interdependent affirmations and negations.
In Hegel, this interdependence is expressed in another interesting way: through the dialectical process. Ultimately, positions are articulated through/in response to contrary positions. Dialogue and progress in philosophy proceed through this negotiating of interdependent affirmations and negations.