"Why then has the fool said in his heart, there is no god (psalms) since it is so evident to a rational mind that thou dost exist in the highest degree of all? Why except that is he dull and fool?" - Anselm
"for example it is said somewhere in the ocean is an island... and they say that this island has an inestimable wealth... it is more excellent than all other countries... Now if someone should tell me... since it is more excellent not to be in the understanding alone but to exist both in the understanding and reality for this reason the island must exist" - Gaunillo
"of God, or being greater than all others, I could not conceive at all except merely according to the word. An object can hardly or never be conceived according to the word alone" - Gaunillo
"god cannot be conceived not to exist... That which can be conceived not to exist is not God" - Anselm
"god without existence would not be god" - Descartes
"I find that existence can no more be separated from the essence of God and the essence of a rectilinear triangle can be separated from the equality of its three angles to two right angles or indeed the idea of a mountain from the idea of a Valley" - Descartes
"existence is obviously not a real predicate" - Kant
"to posit a triangle and yet to reject its three angles if self contradictory but there is no contradiction in rejecting the triangle altogether with its three angles" - Kant
"the real contains no more than the merely possible 100 real Thalers does not contain any more than 100 possible Thalers... the question still remains whether it exists or not" - Kant