The existence of evil and suffering is a significant problem for religious people who have tried to understand and explain their prescence.
If someone is not religious, then evil is just part of our world and has to be accepted - there is nothing we can do about it. However, for religious people there are significant questions:
The Greek philosopher Epicurus (342-271 BCE) claimed that the existence of God proved there is no God.
He claimed that if God cannot stop evil then he is not all-powerful (omnipotent).
He then argued that if God can prevent evil but does not, then God is not good.
He linked these two points together, claiming that if God is all-powerful and good, then evil would not exist.
Finally, human experience is that evil does exist. Therefore Epicurus concluded that God must not exist.
The problem of evil can be regarded as an ‘inconsistent triad’ – in other words, three ideas but only two of them can be true.
As there is clear evidence and experience of evil, either God is not all-powerful (ie He cannot stop evil) or God is not loving and good (ie He does not love us or care enough to stop evil).
The inconsistent triad