The statement "All determination is negation" is a profound maxim often associated with Baruch Spinoza, encapsulating a core tenet of his monistic philosophy. For Spinoza, to define or determine something, to give it specific attributes or limits, is fundamentally to state what it is not.

In Spinoza's system, there is only one infinite, eternal, and absolutely unlimited Substance (God or Nature). This Substance possesses infinite attributes, each expressing its eternal and infinite essence. Any specific attribute (like Extension or Thought) or any particular mode (a finite thing like a human or a stone) is a "determination" of this Substance.

To be a specific mode, for instance, a finite human being, is to be limited. A human is limited by other humans, by physical laws, by its finite duration, and by the attributes that it does not possess. Therefore, to be human is to be a negation of the infinite Substance's boundless potential. If Substance were truly infinite and absolutely positive, it could not have any particular limits. Any specific property or boundary (a "determination") placed upon it, or within it, implies a boundary, an exclusion, a "negation" of absolute infinitude.

Thus, for Spinoza, any finite reality or specific characteristic we can identify is, by its very nature, a negation of the infinite, all-encompassing, and undivided reality of God/Nature. This concept is crucial for understanding his determinism, as every finite thing is determined by other finite things, ultimately flowing from the infinite Substance, whose own being is without negation.