The world feels very different, depending upon who you are, and what you believe.
For some, who believe in joy, and life, and happiness, this world is a gift, and our lives upon it are our contribution to the celebration of life.
For others, who live in pain and desperation, this world is a sad place, filled with loss and heartbreak, and their only hope at a better life is in the afterlife.
For the cultists, for those who see this world as a battlefield of good and evil, and they are on the "good" side, this world is a dangerous place, in which only violent actions can affect positive change to bring about their goals. It is a world in which no action is too extreme, so long as it furthers their goal. Not only will they not be punished for it in the afterlife, but rewarded for it.
For them, this is a holy war. There is no human authority who can tell them otherwise, for they answer only to their god. There is no level of condemnation their fellow believers can level against them that will change their minds.
There is no real way to stop them, because there will always be more of them.
So what can a civilized people do to protect themselves?
Authorities can crack down and restrict the movements of the populace, they can enforce random searches, or subject the citizenry to surveillance, but they will never be able to have complete certainty that they have found every terrorist.
They will never be able to be sure that this will never happen again, because people who are willing to die for a cause are very hard to stop.
But this is true in any free society.
So what do civilized people do, if they can't protect themselves?
Remain strong. Stand up in defiance against those who would hurt you. Hold tight to love, and peace, and each other. Do not let barbarians destroy your world of life, of joy and happiness, and turn it into their battlefield.
Mourn for those who are lost, honor their memories, and try to make sense of the senseless. Words are an empty vessel to those who suffer right now, but in time words are all we will have.
We will remember this in stories, the words of the survivors, and the last words of the victims. For some, these words will never be forgotten.
But for the benefit of future generations, we shall speak of the great courage of the French, who stood together as one against the savage massacre of innocents that occurred in their midst, who showed that love is more powerful than hate, and that fear can never erase who they are.