Usó i Domènech, Josep Lluís, Nescolarde-Selva, Josué Antonio, Gash, Hugh Ontological Argument and Infinity in Spinoza’s Thought Foundations of Science. 2020, 25: 385-400. doi:10.1007/s10699-019-09627-2 URI: http://hdl.handle.net/10045/106749 DOI: 10.1007/s10699-019-09627-2 ISSN: 1233-1821 (Print) Abstract: If the words in Spinoza’s Ethics are considered as symbols, then certain words in the definitions of the Ethics can be replaced with symbols from set theory and we can reexamine Spinoza’s first definitions within a logical–mathematical frame. The authors believe that, some aspects of Spinoza’s work can be explained and illustrated through mathematics. A semantic relation between the definitions of the philosopher and set theory is presented. It is explained each chosen symbol. The ontological argument is developed through modal logic. And finally, we present some conclusions drawn from this work. Keywords:Dictionary, God, Infinity, Modal logic, Ontological argument, Set theory Springer Nature info:eu-repo/semantics/article