This is said in three ways. For either [it can mean] something which neither harms nor helps -- as we say, "a body in the light is not without shadow." [...] Or [it can mean] what is necessary, like a tool or something of the sort -- as we say, "Achilles did the greatest deeds, but not without his spear (for [...] in regard to great deeds, he would not have been able to accomplish great deeds unarmed). Or [it can mean] the condition which hinders -- as we say, "sailing in a storm he was saved, but not without danger."