Are there any classic proofs of the necessity of a mind-independent "reality," along the lines of Anselm's proof of God?

  • I'd suggest making the second part into a question of it's own - I don't know the answer, but it seems more suited to the site that way.
    – DTR
    Commented Sep 5, 2015 at 23:49
  • Thanks, I deleted my reference query about Kant's noumena. What remains may be too broad, but I'll try fishing for a bit. I guess I was picturing answers post-Kantian "turn" to a subject-centered ontology. But by that time, I suppose we don't have curt "proofs" in the Anselm style, at least not on the Continental side. Commented Sep 6, 2015 at 15:47
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    Does Cartesian Circle count? Clear and distinct perceptions indicate existence of reality because God exists and is not a deceiver. God exists and is not a deceiver because Descartes has a clear and distinct perceptions of him. en.wikipedia.org/wiki/Cartesian_circle Ontological argument is itself fallacious, but in a more subtle way philosophy.stackexchange.com/questions/24484/…
    – Conifold
    Commented Sep 8, 2015 at 0:10
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    A Treatise Concerning the Principles of Human Knowledge by Berkeley does come up with a long string of proofs which should adequately answer your query. Commented Apr 18, 2016 at 12:40
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    A fortiori every proof for the existence of god is a proof for mind independent reality, so long as you can exclude the possibility that you are god.
    – KKell
    Commented Apr 19, 2016 at 2:43

2 Answers 2


There are no popular theories pertaining to the "necessity" of an external world. Bishop Berkeley tries to prove the necessity of an entirely mind-dependant world, but direct realists have only refuted their opposition, and not made any solid attempt to defend reality. The only way to have necessary existence of reality is to invoke God as Descartes does when asserting his own existence, and invoking the non-natural opens a theory to more problems than it solves.


You might be interested in Paul Boghossian's Fear of Knowledge. As I recall, though, I did not find his argument for an objectively existing reality (I will use "OER") convincing.

I will point out that the moment one talks about other people (or, for that matter, tables or chairs) he is assuming that there is an OER. If he wants to avoid that assumption, then he has to talk about his own other-people-ish sensory qualia (or about his own table-ish sensory qualia or his own chair-ish sensory qualia). I will also point out that to say that science has the virtue of its hypotheses' being testable once again presupposes OER. Thinking of yourself as interacting with other people (or with tables or chairs) presupposes that you accept that there is an OER (as well as that you derive reasonably reliable information about it, presumably via physical senses). Unless you are willing to restrict yourself to talking about only your own sensory qualia, it is a practical necessity to assume that there is an objectively existing reality of which you gain reasonably reliable information via some informational connection (presumably, physical senses). And to see other people as having moral value, or thinking that they ought to be so treated despite morality's not being objective, requires thinking of them as existing beyond your own mentality--and therefore requires assuming that there is an OER of which you somehow gain reasonably reliable information.

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