The paper aims to present Spinoza’s understanding of the ontological status of finite beings, which was heavily influenced by mathematics, i.e. geometry. Spinoza stratified finite beings into two fairly incompatible layers: the one subjectively conceived, while the other is the objective level. The first level is related to the essence of being that is caused by God through immanent causality: here, we speak of entailment on the logical and epistemological level, and not the level of reality. Unlike essence, existence represents (...) the second level of being: existence is caused by the real finite being through transeunt cause. The first level, by its ontological status, is very close to mathematical entities, therefore the qualification that Spinoza ‘geometrized reality under a species of the essences’. Namely, he geometrized the segment under the scope of ontology, i.e. the essences of finite modes. The final part of the paper is dedicated to one of the main reasons why Spinoza failed to provide a satisfactory solution to this ontological problem, which is not the only such problem of his system. This would be that Spinoza paid too much attention on ethics, to the detriment of metaphysics, i.e. ontology as general metaphysics. For Spinoza, ontology is subjected to epistemology and ethics, therefore the name ‘functional metaphysics’. (shrink)