”When you are studying any matter, or considering any philosophy, ask yourself only what are the facts. And what is the truth that the facts bear out...” –Bertrand Russell
The ‘facts’ are verifiable and stand up to scrutiny. They are not the products of wishful thinking or of our own biases or of our attempts to force the physical world to conform to our ideas about how it is or should behave. The facts are the bare bones of our physical reality, the objects of scientific inquiry, and the fabric of our daily lives.
Indeed, facts are the ultimate arbiters of truth. Statements that correspond to the facts are true and those that do not are false. If a philosophy or science or religion or individual person says “things are …X” or “the members of this group of people are…Y” or “reality is…such and such” it is wise not to simply take their word for it. Take every statement as a hypothesis. Is it true? How do we find out? We find out by figuring out the facts of the situation and testing the hypothesis against them.
As a controversial example, I’ve been told that human beings, unlike any other creature on the earth, have a permanent, eternal Soul. But what are the facts? When I look into this human being here, I find impermanent biological systems, changing cells and bodily processes, ever-flowing thoughts, fluctuating feelings, changing notions and schemas, rapidly-switching states of consciousness, and an ever-shifting imagination. Nowhere here do I find anything like a permanent Soul.
Nor do I have any reason to believe that homo sapiens sapiens, a species which evolved like every other species now alive on the Earth, should possess some permanent metaphysical nature that none of our other evolutionary brothers and sisters in other species possess. Therefore, having tested this belief against the facts–as far as I know them–I find it to be false, that is, to not correspond to the facts. Since I find this belief to be false, I hold it to be a fiction or an illusion and therefore, do not hold this belief.