The colour black has had different symbolic significance for different cultures; the revered Hindu god Krishna is black and the Black Madonna is equally revered in Catholic worship. Black may symbolise academic success and scholarship for black-gowned students and clergy; potency for some sports groups; evil for others and darkness for the explorers and missionaries of the European Enlightenment.

I want to talk about blackness from my perspective and experience as a writer. I was very proud of the release of my novel Wizard of the Crow. On November 10, 2006 the book tour took me to San Francisco, a penthouse guest at the Vitale Hotel, courtesy of Random House.

It was in the hours between breakfast and lunch that I took a newspaper from reception and sat on the terrace of the Hotel’s restaurant enjoying the view of Embarcadero, the harbour-front.

I raised my head to find a suited gentleman who I assumed to be the manager addressing me: “This is for hotel guests,” he said. I was about to explain that I was a guest when it crossed my mind to ask: “How do you know I am not a guest?” As if to say it was not necessary to prove the obvious, he did not respond to the question, but continued reiterating the same fact but with an increasingly peremptory tone.

The tension rose. Curious, I asked him: “You have not even sought to know if I am staying at the hotel?”

This seemed to rile him even more: It was not necessary. The place was for guests. I had to leave.

By now I was determined not to offer any proof or explain that I was a guest, occupant of one of the most expensive suites in the hotel. Not that he was asking for proof or explanation. “Let’s go to reception,” was all I said. He strode ahead of me, furious, determined, I following, curious. When he saw the horror on the face of the hotel manager, he was all abject and sorry.

Let me say for the record that the CEO of Joie de Vivre Hospitality, the parent company owner of the hotel, published a public apology on $450 worth of space, and in negotiations with Priority Africa Network, agreed to conduct diversity re-education of his employees.

He called me at my place in Irvine, South California, to apologise. In addition, he paid $5 000 to a grassroots organisation for anti-racist activism in the Bay area.

Why then am I telling this story on the occasion of the celebration of Africa Day, a time that seems a far cry from the colonial days of my birth and upbringing?

The San Franciscan gentleman never came across as an obvious racist, the fire-breathing nigger-calling type, seeking any opportunity to hurl an insult, the kind that assumes every black person collects food at dumpsites, or foodstamps in the case of the US.

He was totally different from a white guy in New Jersey who once found my wife and me waiting in line to use an ATM and demanded to go ahead of us because we were “cashing a welfare cheque”. We were Kenyans but our blackness made him assume we were recipients of monetary handouts from the government. An undercover police officer happened to be there and stopped what was turning into an ugly confrontation.

Unlike the New Jersian, the San Franciscan did not once utter a word or make a gesture that was overtly racist. But he had something far deeper and more frightening than overt racism: certainty, a certainty arising from a profile of blackness embedded somewhere in his mental makeup, an absolute certainty that in no way, shape or form could I have been a hotel guest.

Even when I gave him an opening to re-examine his assumption, he would not go there. He would not entertain any doubt, the little voice of maybe, that often cautions humans from acting with the uncritical instinct of a beast of prey.

The Sean Bell shooting incident took place in New York on November 25, 2006. A joint team of plainsclothes and undercover NYPD officers shot a total of 50 times at three men as they came from a bachelor party at a nightclub on the eve of Bell tying the knot. Bell died on the morning of his wedding day.

On Februray 5, 1999 a team of New York cops gunned down Amadou Diallo, an unarmed 22-year-old from Guinea, a few metres from his apartment. He was coming home and, from all accounts, there was not even a confrontation. But the police were certain he had a gun. He didn’t. The cops saw a gun where one did not exist.

The pattern in the cases is incredibly similar. Each of the victims was returning home: none was armed. And yet the cases elicited an excess of violence, the kind unleashed by someone who thinks he is in imminent danger. In all the cases, the officers swore they were not driven by racism and yet all of them seemed so certain of what they thought they saw that they rained bullets on the suspects.

And lastly, the case of George Zimmerman and Trayvon Martin.

Zimmerman was captain of a neighbourhood watch in Florida. On February 26 this year, Zimmerman saw an African-American youth, Martin, walking in the street, and shot him dead. As it turned out, Martin was returning to his home in the area. The words that stood out in Zimmerman’s call to the police prior to the killing, at least the ones I saw on TV, were that Martin was walking. “And now he is looking at me.” Three sentences. He is walking. He is looking. He is wearing a hoodie.

A prominent TV show host was later to attribute the killing to the hoodie Martin was wearing and advised black and Latino youths not to wear them. But I could not help asking myself: was it the same self-certainty that made George Zimmerman pull the trigger?

The question was rooted in my own experience with the Vitale Hotel incident. Except for the tragedy, the blame-it-on-the-victim explanation was eerily the same.

The fact is Martin could have been any black person anywhere. It does not matter if fresh from the continent or having an ancestry that goes back to the experience of slavery and colonial plantation, or from Stockholm to receive the Nobel Prize in literature or a visiting African head of state taking a stroll in a quiet neighbourhood.

That self-certainty can condemn anyone to an early death.

In that sense race would seem to trump class. The certainty is based on a negative profile of blackness taken so much for granted as normal that it no longer creates a doubt.

The perception and self-perception of blackness as negative is spread and intensified in the images of the everyday: in the West, TV clips to illustrate famine, violent crimes, and ethnic warfare, tend to involve dark faces. In commercials, TV dramas, in the cinema, one hardly ever sees a really dark person portraying beauty and positivity. A concession to blackness stops at various shades of lighter skin.

No wonder this results in a knee-jerk rejection of the African body.

Afro-American comedian Chris Rock made a documentary, Hair, in which he goes about trying to sell various types of hair.

It is very telling. Whereas European and Asian-type hair has numerous black clients, African hair does not attract a single buyer.

In Africa, Europe and America, skin lightening technology and services are a huge industry. In short, a multibillion industry in the world is built around the erasure of blackness – and its biggest clients are the affluent black middle classes in Africa and the world.

Africa has to review the roots of the current imbalance of power: it started in the colonisation of the body. Africa has to reclaim the black body with all its blackness as the starting point in our plunge into and negotiations with the world.

We have to rediscover and reclaim the sense of the sacred in the black body. At the Seventh Pan African Congress in Kampala (in 1993), I raised this question of the sacred. I wanted us to work on a Pan-African scale, for a political situation where the death of a single African person raises horror and concern in the body politic as a whole. Today the opposite is the case: a white person missing raises more anxiety among African governments than hundreds of missing blacks. We have to take the initiative to fight and right the roots of such differential knee-jerk reactions.

One corrective thing we can do: the African middle class must give up the looting mentality inherited from the colonial era. The political mercenary must give way to the political visionary. This would mean jettisoning that view of progress that sees stability as lying solely in a glossy middle class.

Ours has to be a continuous return and reconnection with the creative base of our being, the working people of Africa. It’s this that gave Africa the power and the strength to fight against the armed might of colonial empires: it’s what will enable Africa to liberate and revolutionise its being. It’s the condition of the ordinary person that should be the gauge of what progress we have made, not that of the pampered middle class.

Most important, Africa must rediscover and reconnect with Kwame Nkrumah’s dreams of a politically and economically united Africa, rooted in the working people of Africa. If we brought together the might of our African and global presence, there’s nothing that could stop Africa being an equal global player. It’s only such an Africa that can contribute to the world and receive from the world on terms of equal exchange and mutual respect.

The world begins at home.

Home begins inside the castle of one’s skin.

This is an edited version of Wa Thiong’o’s lecture at the University of The Free State this week.