Organised by the Centre for Research in Rural and Industrial Development, the two-day international conference will conclude on Friday.
Ansari said Guru Nanak, whose 550th birth anniversary is being celebrated, advocated brotherhood of all humans, espoused the cause of downtrodden, and advocated what in modern terminology is called interfaith dialogue.
"Decades earlier, Rabindranath Tagore had called nationalism 'a great menace', describing it as 'one of the most powerful anaesthetics that man has invented'. He had expressed himself against 'the idolatry of the nation'. Albert Einstein considered it 'as infantile disease'," Ansari said.
Patriotism, on the other hand, is defensive both militarily and culturally, he said.
"It inspires nobler sentiments but must not be allowed to run amok since in that condition it 'will trample the very values that the country seeks to defend'."
But nationalism has come to identity itself over and above individual moral judgement, increasingly been confused with patriotism, and if done so with impunity might lead to unstable and explosive conditions, the former vice-president asserted.
"Nationalism in its strident form is inseparable from the desire for power. It is an 'ideological poison' that has no hesitation in transcending and transgressing individual rights," he said.
Nationalism means identifying oneself with a single nation, placing it beyond good and evil, right or wrong, suspending individual judgment, and recognizing no other duty than that of advancing its perceived interests, Ansari said.
"It is often confused with patriotism and used interchangeably. Both are words of unstable and explosive content and so need to be handled with care since they differ in meaning and content," he said.
So, the former vice-president said, humanity could only be saved if both these pandemics religiosity and strident nationalism are evaded and replaced by human behaviour in light of collective experience and moral guidance.
"The conclusion is unavoidable that both religiosity and strident nationalism are undesirable. Alternatives to both are within human reach. We are thus driven to accept the logic of the teaching of all religious personalities that salvation of humanity and of human happiness lies in the promotion of peace and harmony through tolerance, dialogue, accommodation, and acceptance, he said.