The one who wonders why evil exists in this life, taking it as a pretext for negating the existence of God only reveals his shortsightedness and his fragile thinking in realizing the wisdom behind this, and reveals his lack of awareness about underlying issues. By posing such a question, the atheist implicitly admits that evil is an exception.
Therefore, before asking about the wisdom behind the existence of evil, it is worthier to ask a more realistic question, which is: How was goodness brought into existence in the first place?
Undoubtedly, the most important question to start with is: Who brought goodness into existence? We must first agree on the starting point or the original or prevailing principle, then, we can search for the causes behind the exceptions.
Scientists, in the beginning, lay down fixed and definite laws for physics, chemistry, and biology, after which they conduct a study on the exceptions and cases that deviate from such laws. Similarly, atheists cannot get past the hypothesis of the existence of evil unless they first admit the existence of a world full of beautiful, organized, and good phenomena beyond count.
Comparing the periods of health to those when diseases spread during the average lifetime, or the decades of welfare and prosperity to periods of destruction and ruin, or the centuries of calm and tranquil nature to periods when volcanoes erupt and earthquakes strike all bring up one question, which is: Where does goodness come from in the first place? A world built on chaos and coincidence can never produce a good world.
Ironically, scientific experiments confirm this. The second law of thermodynamics states that full entropy (degree of disorder or randomness) in an isolated system away from any external influence will constantly increase, and this process is irrevocable.
In other words, organized objects will collapse and vanish forever unless they are bound from the outside. Thus, blind thermodynamic forces could never produce anything good by itself or as good on a broad scale as it is without the Creator organizing such random phenomena that appear in magnificent things like beauty, wisdom, joy, and love. All this came after proving that goodness is the basic rule while evil is the exception and that there exists a Capable God, a Creator, and a Sovereign Who manages all affairs.