During a recent online discussion I discovered, somewhat to my surprise, that there is no general agreement on what the word “exist” means. Everyone has an intuitive understanding of it but when it comes to an explicit definition of the word there is no consensus, and indeed philosophers have written a vast literature on the topic of ontology, or what exists.
Dictionaries don’t really help; for example Oxford Dictionaries gives a nicely circular set of definitions:
Exist: 1. have objective reality or being
Reality: 1. the state of things as they actually exist
Being: 1. existence.
Of course physicists have a perfectly good operational definition: something exists if it is capable of making a detector go ping. Try arguing that, however, and you’re immediately accused of materialism, physicalism, scientism, being blind to possibilities beyond a very narrow world-view, and a host of similar sins (I plead guilty to at least the first three). Continue reading