On the origin of "De mortuis nil nisi bonum"
Why do we feel that it is not appropriate to gossip dead people?
Dead people are not rivals. This simple fact could explain why we are less inclined to gossip about people after they have died. We are less inclined to be angry at them, to hold a grudge. They are no longer a threat. There is a certain sense of inappropriateness in doing that. Like flogging a dead horse .
The Latin phrase is De mortuis nil nisi bonum or Do not speak ill of the dead.
Consider how the famous physicist, Freeman Dyson, describes his relationship with philosopher Ludwig Wittgenstein before and after the latter's death:
I decided that he was a charlatan using outrageous behavior to attract attention. I hated him for his rudeness. Fifty years later, walking through a churchyard on the outskirts of Cambridge on a sunny morning in winter, I came by chance upon his tombstone, a massive block of stone lightly covered with fresh snow. On the stone was written the single word, ‘WITTGENSTEIN.’ To my surprise, I found that the old hatred was gone, replaced by a deeper understanding. He was at peace, and I was at peace too, in the whiten silence. He was no longer an ill-tempered charlatan. He was a tortured soul, the last survivor of a family with a tragic history, living a lonely life among strangers, trying until the end to express the inexpressible.
Was Dyson’s “old hatred” toward Wittgenstein replaced by a “deeper understanding” only because he gained knowledge about the tragic history of Wittgenstein’s family? I think it’s more than that.
The death of a person can change emotions in such a radical way that people can switch from pre-death gossip and resentment to posthumous praise and respect for the deceased.
But how is this possible if emotions we have towards other people are just evaluations (or a consequence of evaluations) of those people? Death did not change what these people were or did, so some naive psychologist could, perhaps, expect that emotions and attitudes would remain unchanged.
One possible answer: death does not change what people were, but it changes what they can do. There is nothing a dead man can do.
The emotions we have towards other people are not just our evaluations of those people, representations of their character stored somewhere in our minds. Rather, they are of a strategic or instrumental nature.
Some of this "strategic nature" is well expressed in the humorous comment that "people are more opposed to fur than leather (as clothing) because it is safer to harass rich women than motorcycle gangs."
From an evolutionary perspective, the emotion of anger is part of a bargaining process whose function is to encourage the object of anger to put more weight on the well-being of the angry person. But after the hated person has died, there is no bargaining game to be played—and so anger and hatred give way to eulogy.
Addendum (March 5, 2021): One reader asks me why we need to praise a person all of a sudden now that he or she is gone. Instead of praising her, we can simply keep quiet. It seems to him that my explanation fails to explain why we go to that extreme.
Maybe I should have been more precise about what my explanation explains. It explains the change in attitude towards the deceased. More specifically: a change in the emotional attitude (although I don't think it must necessarily be just a change on the emotional but also the cognitive level, but let's leave that aside for now).
The change from gossip to praise is just one special, and extreme, case of “change in attitude”. Instead of praising, we can be silent, true. And I'm sure many are "silent." Now, why does the death of a person lead to a transition from a negative to a positive attitude towards the deceased in some people? Here’s one possible answer: a person feels that the deceased person has indeed done something good, but only after his or her death can he or she “admit it”.
We can imagine life as an arena within which people compete over limited resources. Individual status is related to access to resources. Paying tribute to a rival raises the status of the rival. In that sense, the death of a rival represents his exit from the arena, so that paying him a tribute and respect no longer carries the same practical consequences as if he was still in the arena, i.e. if he was still a competitor for earthly resources.
Here we can understand "rivalry" in the most general sense when one person sees another as an obstacle to achieving their goals. Similarly, "resources" can be understood in a more general sense as any value that people care about: from material things to other people's attention.
A dead person cannot convert his status, fame, or respect of the living into the acquisition of resources, so his rivals do not suffer the same cost if they give him this recognition after death as during his life. In this sense, there is some truth in Nietzsche’s aphorism that some people are born posthumously.