First of all, the article analyzes, in panorama, Spinoza’s ontology. Secondly, it shows how, from the concepts present in the ontology, the author derives others, as man, desire, joy and sorrow, hope and fear, security and despair, action and passion. From the relationship between ontology, men and desire - as well as from the other affects -, are extracted, in brief considerations, some Spinoza ́s political thesis. In this argumentative movement, the hypothesis is that many Spinoza’s political thesis a rise from its ontology and its conception of man as desire and potency variation. The concept of desire is analyzed in the light of the variation of potency and the theme of natural right, which in Spinoza is identical to potency. When the s...