How did Edmund Husserl distinguish knowledge of essences from knowledge of facts?

Edmund Husserl distinguished between knowledge of facts and knowledge of essences by employing a methodological process known as the eidetic reduction.21

While factual knowledge concerns contingent, individual objects that occur in specific ways, knowledge of essences seeks the eidos—the invariable, universal, and essential structure of a thing. Husserl argued that philosophy must move beyond the empirical, which possesses only relative validity, to achieve a rigorous, scientific knowledge of these essences.213

To achieve this, Husserl utilized the method of free variation. This process involves:14
* Starting with facts: The philosopher begins with a concrete, factual object.1
* Imaginative variation: One creates a multiplicity of variations of the object in the imagination, intentionally altering its aspects.21
* Identifying the invariant: By focusing on what remains unchanged throughout these variations, the philosopher identifies the "invariant" or the essence that maintains itself.21

Through this reduction, Husserl "brackets" or suspends belief in the actual existence of factual objects, allowing the researcher to focus exclusively on the essential structures of consciousness and their corresponding objective entities.213