The most challenging argument against theism is based on the existence of evil. Much evil is caused by sinful humans. God gives us freedom, which is good, but some of us misuse our freedom and do evil. Thus God is not to blame. But what of natural evil – like earthquakes, floods, spiders eating moths and lions eating zebras? This can be explained by blaming Satan.
God also gave Satan, and angels in general, freedom. Satan and the other fallen angels misuse their freedom and do evil. Again God is not to blame. Far from being responsible, God gave His Son to die a cruel death, allying Himself with those who suffer.
What would the world look like if Satan did not exist? God made a universe fine-tuned to produce life, but this life can take many forms. Without Satan maybe there would be no livings things that could suffer – and hence no natural evil. Absent any of the complex animals that feel pain, the world would be a sort of Precambrian paradise. Cyanobacteria and sponges, fronds and discs would drift and sway in the currents, the whole vast ocean innocent of suffering.
I wish I could wander around in those primordial times – before fear, before sorrow – walk across the velvety silt, wriggle my toes in the warm brownish ooze. See the multicolored procaryotes gambol in the ancestral Panthalassic Sea.
The tide is full. Night comes. Watch the glistening stromatolites rising from the sea under the enclosing black dome of the sky.
Pre-Raphaelite, prehistoric, prelapsarian, earlier still Precambrian.
Perhaps God arranges for life on other planets to seldom proceed much beyond the single cell level. An atmosphere with a generous portion of oxygen is associated with complex life. Maybe such an atmosphere is rare.
Maybe life usually remains on a prokaryotic level.
God can bring forth good out of evil. God has created all living creatures. Animals and plants (and fungi too) are wonderful! Humans are created by God in His own image. Suffering helps us achieve redemption.
But I don't think man will stop searching for the lost paradise until it's found.
The author, like Teilhard de Chardin, tries to bring together paleontology and theology. Unlike de Chardin, however, the author considers progress neither inevitable nor necessarily desirable.
The birth of eukaryotes about 2 billion years ago may betray Satan's involvement in prehistoric times just as 1917 (Bolshevik Revolution, U. S. entry into WW I, Balfour Declaration, and Armenian Genocide) may betray Satan's involvement in more recent times. In both cases all Hell broke loose, it was pandemonium.
Another possible world without evil: a realm containing complex animals that experience little or no pain. Think of near-immortal animals that clone themselves and do not fear death. It should be noted that some biologists consider such serene complex animals unlikely.