There is no way to prove anything exists outside of our consciousness

Just because we "agree" on something doesn't make it reality. We believed wholeheartedly in geocentrism and that turned out to clearly not be reality. I'd ask con to please use real arguments and reasons rather than relatively meaningless statements like "if we agree that things exist, then they exist."One of my favorite all-time quotes: Indeed, in a way, we're always hallucinating. “It's just that when we agree about our hallucinations, that's what we call 'reality. Please check out the TED Talk it's from here: https://www.ted.com... before continuing.There is not one thing in this universe that you can "prove" exists. You can tell me other people see it or feel it or hear it. You can tell me all sorts of characteristics of it. But you can't prove that it's "real". You can't prove that it isn't part of some elaborate dream created by a being far more intelligent than us capable of rendering such realistic simulations.Consider Decartes' Evil Demon: The evil demon, also known as malicious demon and evil genius is a concept in Cartesian philosophy. In the first of his 1641 Meditations on First Philosophy, Descartes imagines that an evil demon, of "utmost power and cunning has employed all his energies in order to deceive me." This evil demon is imagined to present a complete illusion of an external world, so that Descartes can say, "I shall think that the sky, the air, the earth, colours, shapes, sounds and all external things are merely the delusions of dreams which he has devised to ensnare my judgement. I shall consider myself as not having hands or eyes, or flesh, or blood or senses, but as falsely believing that I have all these things.Consider the Brain in the Vat: The Brain in a Vat thought-experiment is most commonly used to illustrate global or Cartesian skepticism. You are told to imagine the possibility that at this very moment you are actually a brain hooked up to a sophisticated computer program that can perfectly simulate experiences of the outside world. Here is the skeptical argument. If you cannot now be sure that you are not a brain in a vat, then you cannot rule out the possibility that all of your beliefs about the external world are false. Or, to put it in terms of knowledge claims, we can construct the following skeptical argument. Let “P” stand for any belief or claim about the external world, say, that snow is white. If I know that P, then I know that I am not a brain in a vat I do not know that I am not a brain in a vat Thus, I do not know that P. The Brain in a Vat Argument is usually taken to be a modern version of Decartes' argument (in the Meditations on First Philosophy) that centers on the possibility of an evil demon who systematically deceives us. The hypothesis has been the premise behind the movie The Matrix, in which the entire human race has been placed into giant vats and fed a virtual reality at the hands of malignant artificial intelligence (our own creations, of course). Donald Davidson also emphasizes this aspect of metaphysical realism: “metaphysical realism is skepticism in one of its traditional garbs. It asks: why couldn’t all my beliefs hang together and yet be comprehensively false about the actual world?” (1986, 309) The Brain in a Vat scenario is just an illustration of this kind of global skepticism: it depicts a situation where all our beliefs about the world would presumably be false, even though they are well justified. Thus if one can prove that we cannot be brains in a vat, by modus tollens one can prove that metaphysical realism is false. Or, to put it in more schematic form: If metaphysical realism is true, then global skepticism is possible If global skepticism is possible, then we can be brains in a vat But we cannot be brains in a vat Thus, metaphysical realism is false (1,2,3) I'd highly recommend this summary on Cartesian Skepticism: In summary, I defy con to come up with one single fact...an objective piece of reality, that they can verify the existence of anything they aren't present to perceive let alone can even prove the existence of if in plain site. Seeing a red ball doesn't mean it isn't part of a virtual reality world. Look at something as simple as the Sims video game series which has existed for decades. The Oculus Rift now.