No reason justifies disbelief.

[tackattack]

that's a new one. Please define reasoned disbelief @BrianSoddingBoru4

I thought I had, but I'll have another go.

Reasoned disbelief is the rejection of a proposition when there is neither convincing evidence nor compelling arguments to support the proposition.  Let's do Bigfoot as an example.  I disbelieve in Bigfoot because the evidence for Bigfoot simply isn't there - no bodies, no bones, no adolescents, no scat, no hair, no nothing.  Believers use all manner of specious arguments to explain away this (for them) disturbing lack of evidence: Bigfeet are too smart to get caught; Bigfeet are hyperdimensional beings; Bigfeet are aliens; and so on.  Given the non-existence of evidence and the non-compelling nature of the explanations, I make the reasoned choice to disbelieve that Bigfeet exist.

To be fair, there is also 'unreasoned disbelief'.  Things like, 'I don't believe in Bigfeet because I'VE never seen one' or 'My spirit animal told be not to believe in Bigfeet.' 

Hope this helps.

Boru

Yes that helps. I always saw it as belief is a threshold thing. You either had justification or it didn't meet a level of criteria. If it surpassed your threshold you believed, if you didn't your disbelieved. You make it sound here as if you're positively positing arguments against nothing.