3 but God said, 'You shall not eat of the fruit of the tree that is in the midst of the garden, neither shall you touch it, lest you die.'"
4 But the serpent said to the woman, "You will not surely die.
And the end of the attack by Satan is to flat out contradict God. However, even at this point he is twisting meanings because he knows full well that the death spoken of is real.
Perhaps in the mind of Eve there were two competing truths held side by side. One was that God said they will die, the other was that Satan said they will not die. Both can't be true, and God is clearly the authority, so why did Eve do it? Perhaps she chose to give each death a different meaning in her mind, or that the death God spoke of was the death of ignorance (since they would now know good and evil).
Whatever the reason, Eve went against God's command, and Adam followed, leading to the curse of all Creation. Earthquakes, volcanoes, tsunamis, deficient genetics + mutation, sickness, and sin, sin, and more sin; this was the curse which the first act of disobedience brought upon us. And which we continue to increase by our repeated breaking of God's commands.