It was a challenge to me on an internet site.
One answer is that if a reality 'out there' is only speculation, then that there is no reality out there is also speculation.
Consciousness does not confirm either case and seems to lack a clear connection to the subject.
Knowledge and judgment are the answers here. They tell us that our experience of what may or may not be out there broadly coincides with the experience of entities all around us; and that those entities are clearly not us
but otherwise appear to act like us.
What's more, our cat acts in response to our surroundings. As two or three of those entities might jump at a sudden noise or walk round something in the way, so does our cat.
Bertrand Russell was useful on this. He said if a thing is not certain or is unprovable, it’s best to go for what is probable.
It’s at least probable that ‘our’ world is ‘out there’ as
a cat’s is. It’s just that we are able to speculate that it isn’t. No cat has
been known to do this.
