A turnip is not all-powerful, all-knowing, and perfectly good, so the argument would not apply to a turnip. As the atheist looks at the world around her, she finds instances of gratuitous evil—pointless evils from which no greater good results. She concludes that these instances of unnecessary evil neither preserve free will nor promote the value of society or the well being of humans. The question is why an omniscient, omnipotent and wholly good God would allow the extreme gratuitous suffering we see in the world. there is no suffering in heaven. Why then is it necessary that there be suffering on earth. The existence of free will does not answer the question as to why a small child would suffer. After all, a child has done nothing wrong to deserve extreme gratuitous suffering.
The only argument against the existence of God that I see as having any potential merit would be the existence of evil. The others fall quickly when we focus on the reality of existence, beauty and truth. But then, even this one, with the image of Christ on the cross, the question is transformed into wonder - a God who suffers with us, a God who had intended to keep it for Himself, for the salvation of a free creation, until we grabbed and ate of that fruit. God is Love and Paul outlines its features.
Before we can ask why is evil, we must understand what it is. In a universe that is grounded in a loving act of creation, It involves a departure from that Centre. We disconnect from the eternal benevolent will, through acts that are unloving. With that, we depart from our eternal Home, a prodigal son. Evil includes something out there to harm us, but it can be known intimately and fully as it exists within us.
Evil exists as a potential, a choice to put ourselves at the centre of our existence, that in surrendering we demonstrate our love. Through our actions we participate in our own creation as loving persons. Giving into what is sin, it takes hold and grows until the lust leads to greater and greater harm not only to others, but to our eternal soul.
Suffering usually comes from the unwilling loss of something that was transient and never really ours. From money, power, honour and pleasure to our very relationship with God, it is all given, however hard we have worked to attain those fruits of existence. Like Job, when life hits us hard, within the context of the greater reality we can only affirm, “I am unworthy—how can I reply to you?" and "Surely I spoke of things I did not understand, things too wonderful for me to know . . . My ears had heard of you but now my eyes have seen you. Therefore I despise myself and repent in dust and ashes.” For those who do not recall the story, after Job had prayed for his friends, the Lord gave him much more than he had in every respect. And that’s the way it works, and even while we are here on earth. The aim is to know and love God. Jesus Christ has made it possible to know Him.
Actually, all religions arise from the problem of evil in life. Even when we are in wonder over something beautiful, a truth that pierces the fog of ignorance, the amazingness of life, those moments are often brief, and we are left to grieve what we have lost. The answer to any question regarding the existence of God lies in the reality of the relationship we have with Him. How badly do we want to know Him?