He was delivering a lecture in honour of ANC founder Pixley ka Isaka Seme at the University of Fort Hare, in Alice, Eastern Cape.

"As we remember him [Seme], we invite intellectuals and academics in our country to play a constructive role in the reconstruction and development of our country," he said.

"As we build our young nation, we need our intelligentsia to contribute to a public discourse on whether we are achieving the goals of building a non-racial, non-sexist South Africa."

Zuma said constructive appraisals and criticism from an Afro-optimistic perspective would be helpful in building South Africa and Africa.

He said the ANC owed its existence to Seme.

"He is the father of ANC unity and collaboration. He wanted to see unity beyond ethnicity and tribalism.

"We owe the existence of the ANC to this great man, who made a notable contribution to the development of our consciousness and national spirit," Zuma said.

Seme would also be remembered for his interest in the arts, and especially in respect of writing and the media, he said.