In the aftermath of an atrocity as horrifying as the Paris murders on Wednesday, it is more important than ever to be crystal clear about the freedoms that we hold most dearly.
Freedom of expression, which must always include the freedom to offend and to ridicule. Satire is an essential part of a democracy. Incitement to hatred and to violence are crimes; incitement to mockery is not.
Freedom of religion, including religions deemed offensive by others, so long as they do not impinge on the rights of non-adherents or coerce non-believers into acceptance of their teachings.
Freedom from fear, including the fear of being different, or of speaking out, or of questioning majority beliefs. Above all, the freedom from the fear of being murdered.
Democracies are not "under attack" by jihadis. (And let's hear no more about the threats to "Western" democracies, given that India, Pakistan and Indonesia have all suffered in exactly the same way as Paris, Madrid, London and New York. How quickly we have forgotten the massacre of 132 schoolchildren in Peshawar just last month.)
The language of war is grotesquely inappropriate, as surely we should have learned post-9/11. To use it is to fall into the trap set by mass murderers. Those who kill, no matter for what reason or clothed in what rhetoric, are killers, and should be prosecuted as such, in exactly the same way as any other law-breakers. They are criminals, not holy warriors, however they might choose to describe themselves.
Let's take a leaf from Norway's book, and recall how it dealt with Anders Behring Breivik, the man who slaughtered more than 70 people, most of them teenagers, in 2011. He, too, described himself as an ideologue, but he was prosecuted as a common criminal.
Tolerance is a value to be cherished, but there is no virtue in tolerating those who murder. The only effective way to counter the threat posed by killers like the Paris gunmen is by good police work based on good intelligence work, carried out with full regard for the basic human rights to privacy and freedom of belief.
A mature democracy must be able to tolerate those who preach against democracy. But it can never tolerate those who kill, or seek to kill, those with whom they disagree. It is not a difficult line to draw.
In a free society, you are free to believe whatever you like: that the earth is flat, that the moon is made of green cheese, or that God is alive and well and running a corner shop in Neasden. Likewise, I am free to mock you, laugh at you and offend you -- but I am not free to kill you, or to incite others to do so.
It is futile to talk of "defeating" those who think differently. But it is far from futile -- indeed it is an absolute necessity -- to prevent them from using violence in the furtherance of their beliefs.
Charlie Hebdo is often offensive, deliberately provocative and frequently vulgar. That is its point -- and that is the point of a free society. The kind of freedom I value includes the freedom to be all those things, as well as the freedom to protest against it, peacefully and within the law.
There is a vast gulf separating the mindsets of those who used their guns to kill in Paris and those who use their pens to mock. It is a gulf that cannot be bridged. But it was succintly and accurately defined by The Guardian's media commentator Roy Greenslade, professor of journalism at London's City University.
"Satire challenges sacred cows, but it does not slaughter them. Satire hurts, but it does not cause physical injury. Satire wounds, but it does not kill."
And that is why the pen will always be mightier than the sword.