Altogether now: Nothing is known absolutely, nothing is certain. Everything requires some iota of faith.
Scenario: Brain in a jar being fed hilarious systems such as logic and mathematics which are, really, utter bunkum. Those outside the jar laugh at the poor brain’s inability to grasp that nothing exists and everything exists simultaneously.
Altogether now: This scenario is *not falsifiable *. This scenario is *not impossible *. We all have faith that this scenario is not the case, that our lives are “real”.
Ahhh …and rest.
Now then, what probability shall we all ascribe to this scenario being the case? >50%?
Does any of us actually believe it? Don’t bother trying to answer if so, the straps on those jackets are pretty strong.
About 1%? I’d say you’re still a nutter, but fair play to you.
I think we can all agree, vanishingly small, but still very definitely NOT zero.
Unfortunately, the nonimpossibility if this scenario means that the words know, categorically, deny, falsify, certain, sure, definite, evident etc. must, I’m afraid, fall from the dictionary, never again to be used by intelligent speakers of English.
But wait. Could we use them as though, afterwards, we were muttering under our breath “assuming I’m not a jar dweller programmed with balderdash”? When I say “I know I exist”, can my whispered addendum render the word useable again in conversation with my peers? Hurrah! Flee, pedants, and let us reclaim our language!
Now, let us go further, having taken on faith that the universe exists. Is it possible that all this talk of billions of years passing before my existence is mere rumour, that the universe came into existence simultaneously with me and I am the victim of some elaborate hoax? Of course it is possible, like the nonsense-fed jar. However, again, for me to ascribe to this scenario any more than the tiniest glimmer of a chance would, I hope, cause some concern amongst my friends and family with regards to my health and happiness.
All of these possibilities are of an entirely different order of magnitude to, say, whether or not the defendant is lying or whether or not Liverpool FC will win the Premiership. These are reasonable beliefs. (Well, alright, the Reds are stuffed). Might I redefine the word “know” to mean “believe that which is beyond reasonable doubt”?
With most people, probably. With philosophy fans? Some chance.