|Existence, philosophy, logic: the fact that there is something to which properties can be attributed. That does not mean that something has to be given immediately or can be perceived by the senses. See also ontology, properties, predicates, existence statements, realism, quantification, ascription.|
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existence / nonexistence / existence assertion: one can deny the existence of a thing - that would often be incorrect, but never formally contradictory!
Existence is all in all, externally and accidentally for people.
Sartre: there is no human essence, we have existence but no essence.
No doubt there are terms from the mere meaning of which already follows that they have pieces of evidence in the real world. Only none of them accomplishes what Descartes demanded from the term God.
E.g. the concept of concept has itself for example. E.g. a word is a word. It would be quite cranky to ask if there were words! Without them it would be impossible to formulate a doubt.
A. C. Danto
The Philosophical Disenfranchisement of Art (Columbia Classics in Philosophy) New York 2005