Yes your correct Spud everything should be questioned.
Now here's a way to perhaps know one way or other about a belief.
That is to put ones past experiences aside and with that open mind, under your own control, test what you feel is detrimental to your beliefs.
I realise that it would be difficult to do this but all the same many people put aside many things because not only through bad experiences but were coerced into something involuntarily.
I am not trying to induce beliefs because I know better than to even attempt to do that. In actual fact it will most likely add further strings to your bow (if I can put it that way) or it just might leave one with an open mind and you say "whatever".