Reasonableness is a matter of degree. Beliefs can be very reasonable (Japan exists), fairly reasonable (quarks exist), not unreasonable (there's intelligent life on other planets) or downright unreasonable (fairies exist).There's a scale of reasonableness, if you like, with very reasonable beliefs near the top and deeply unreasonable ones towards the bottom. Notice a belief can be very high up the scale, yet still be open to some doubt. And even when a belief is low down, we can still acknowledge the remote possibility it might be true.How reasonable is the belief that God exists? Atheists typically think it very unreasonable. Very low on the scale. But most religious people say it is at least not unreasonable (have you ever met a Christian who said 'Hey, belief in God is no more reasonable than belief in fairies, but I believe it anyway!'?) They think their belief is at least halfway up the scale of reasonableness.Now, that their belief is downright unreasonable might, in fact, be established empirically. If it turned out that not only is there no good evidence of an all-powerful, all-good God, there's also overwhelming evidence against (from millions of years of unimaginable and pointless animal suffering, including several mass extinctions - to thousands of children being crushed to death or buried alive in Pakistan earthquake, etc. etc. etc.) then it could be empirically confirmed that there's no God.Would this constitute a 'proof' that there's no God? Depends what you mean by 'proof'. Personally I think these sorts of consideration do establish beyond any reasonable doubt that there is no all-powerful all-good God. So we can, in this sense, prove there's no God.Yet all the people quoted in my last blog say you cannot 'scientifically' prove or disprove God's existence. If they mean prove beyond any doubt they are right. But then hardly anything is provable in that sense, not even the non-existence of fairies.