FIRST WORDS the Evil is something that alone if characterizes favours, first, the existence of the Good. However, when characterizing itself, the Evil finishes for characterizing the Good, that is, it characterizes that the Good is Good. The Good and the Evil are forces that if would annul in case that only one existed. For example, the health is something good, but for who it only knows the illness, that is something bad. However when we have health we do not give to importance to the type of drink or food that we consume.
The important one is that they are pleasant to our palate. However, when we adoecemos is that we perceive that the health is something good, that is, for intermediary badly I discovered it that the good is good. This relation is directly proportional, that is, how much bigger it will be the evil, more certainty we will have of that the good is good. In the example in question, how much bigger more certainty will have the patient of that will be the disease the health is something good. Soon, the evil of the illness characterizes the benignancy of the health. But, illness does not exist without it has the health first. Therefore, badly it characterizes the good, but its existence depends on the previous existence of the good.
Many, or all, condemn Adam and Eva for having eaten the fruit of the tree of the knowledge enters the Good and the Evil. For we are very easy to say that what they had made was not correct, but we only know of this because we are experts of the sin. Certainly that Adam and Eva did not know that the perpetual life was something good, until knowing the death. After this, they had started to give value to the fruit of a tree that always was to the disposal of them, but them it seemed so normal how much to the others, therefore it did not give importance to it: The Tree of the Life.