Alexander, in my opinion asking “how do you know?” is the wrong way to go about it. If someone is making a positive claim (God exists; unicorns exist) then that person has the burden of proof. It is perfectly reasonable not to believe (in God or unicorns) when that burden is not met.

The Stoics understood this, which is why they came up with positive arguments. Unfortunately, they were all variations of what we today call the design argument. Which has been soundly refuted by David Hume and Charles Darwin.

Written by

Ethics, general philosophy, and philosophy of science. Complete index, by subject, at https://massimopigliucci.com/essays/

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store