Answer:
In 2006, I gave some lectures at Harvard during which I called for a month, a week -- a day even -- of collective mourning for the millions whose souls still cry for proper burial and mourning rites. These lectures have now been published under the title: Something Torn and New. I did not know then that others were thinking along the same lines. I am glad that this day is being commemorated at the United Nations, but it should be actively observed in the whole world, as slave trade and plantation slavery were of prime importance in the making of the modern world. But what was a gain for the world, especially in the West, was a loss for Africa. Here I am not simply talking about the loss of human lives, power, resources, the economic loss for Africa and gain for the world: Slave trade and slavery were a historical trauma whose consequences on the African psyche have never been properly explored.
It is well known that both a person who perpetrates trauma and one who experiences it can often shut the trauma in a psychic tomb, acting as if it never happened. The recipient does not mourn the loss and the perpetrator does not acknowledge the crime, for you cannot mourn a loss or acknowledge a crime you deny. This can occur at a community level, where horror committed to a group is kept in a collective psychic tomb, its reception and perpetration, passed on in silence, which of course means that there is no real closure and the wound festers inside to haunt the future.
The West has never properly acknowledged this crime against humanity, for to acknowledge is to accept responsibility for the crime and its consequences. One can, of course, see why the perpetrator of a crime may want to forget it: uneasy lies the crown on the heads of they who have committed crimes against humanity. But post-colonial Africa has also never properly mourned this trauma on its own continent as well as its diasporic communities in the Caribbean and America. In Africa and the world, slave trade and plantation slavery have never been accepted in body and mind for what they were: genocide, holocaust, displacement of unprecedented historical and geographic magnitude. It was Hitlerism long before Hitler, to borrow the phraseology from Aimé Césaire in his book, Discourse on Colonialism.
The economic consequences are obvious: the most developed countries in the West are largely those whose modernity is rooted in the Transatlantic slave trade and plantation slavery. The African body was a commodity; and manpower, a cheap resource. Note that this was continued in the colonial era where, once again, African human and natural resources were cheap for the colonialist European buyer who determined the price and worth of that which he was buying. Don't we see echoes of that today in the unequal trade practices where the West still determines the price and worth of what it gets from Africa while also determining the price and worth of what it sells to Africa?
It is not a strange coincidence that the victims of slave trade and slavery on the African continent and abroad are collectively the ones experiencing underdevelopment. For example, Haiti in the 18th century was the main economic mainstay of France, the coveted price by the major European powers of the time; today it is the most economically deprived in the Western world. Haiti's story is also that of Africa and the African people as a whole. The majority of the homeless in the world still come from communities that were the victims of the slave trade and the plantation.
But that is obvious. It's the moral consequences that deeply worry me -- the negative perception of Africa and Africans by others, and the negative self-conception of Africa and Africans by Africans. Those two conceptions have common ground in the devaluation of African lives. Massacres and genocide can happen in Africa, as in the case of Rwanda, with the world looking on. African governments can mow down their people and go to bed and sleep soundly as if nothing has happened; politicians who settle political disputes by inciting ethnic cleansing (and counter-ethnic cleansing) can go to sleep with consciences undisturbed by what they have brought about. Any life lost is, of course, horrifying, but we have seen how frantic the world and Africa become if a white European hostage is missing or meets death in Africa. It shows an indifference towards the descendants of slaves and deep concern for the descendants of slave owners.