He warned of dangers to the republic if there was no unity and respect for diversity, secularism and pluralism. "The nation is deeply concerned at the recent tragic instances of blatant violation of the right to freedom of thought, belief, speech and expression in our country by some violent extremist groups.
"The assault or murder of thinkers for no more than disagreement with their views, or (of people) because of the food they eat, or their caste, cannot be justified on any grounds. Nor can the suppression of the right to dissent be allowed," he said in his inaugural address at a conference in New Delhi ahead of the 125th birth anniversary of Jawaharlal Nehru.
The two-day meet is being held at a time when the legacy of the first prime minister is under assault and in the backdrop of Dadri lynching, beef row and other incidents. The incidents have triggered off an award-returning spree by litterateurs, artistes and film-makers.
The senior Congress leader said that all right-thinking people have condemned such incidents in the strongest term as an "assault on the nation".
Unity and respect for diversity, secularim and pluralism are vital of the survival of the republic, he said, adding that peace is essential not only for human existence and survival, but also for economic and intellectual growth and development.
"Capital is likely to be frightened away by conflict", Singh, who is known as the architect of India's economic reforms, observed in an apparent message to the Narendra Modi dispensation that is working hard to seek investment and promoting "Made In India".
He said suppression of dissent or free speech poses a grave danger for economic development. "There can be no free market without freedom."
Freedom is a foundational value that lies at the heart of the Nehruvian idea of India, Singh said.
"It is widely known that freedom feeds the soul and the heart. What is less appreciated is that freedom is also essential for economic development," he said, noting the unimpeded flow and exchange of ideas are essential to build economic prosperity.
Holding that there is no progress without opposition, he stressed that the prerequisite for innovation, entreprenuership and competition is an open society and a liberal polity where individuals are free to pursue their ideas.
"No peace without freedom; No freedom without peace: Securing Nehru's legacy and India's future: Agenda for Action" is the theme of the conference organised by Rajiv Gandhi Institute of Contemporary Studies, New Delhi.
The former Prime Minister said secularism is an "article of faith for the IndianRepublic. Secularism protects the fundamental freedom of every citizen to faith, belief and worship. All religions are equally respected under the Indian Constitution.
"Religion is a private matter in which no one, including the State, can interfere except to the extent necessary to protect the freedom of others. In a secular republic, no religion can become the basis of public policy or governance, nor can any religious belief be imposed on anyone," he remarked.
Singh said that it is necessary for all people who support the Nehruvian idea of India as a liberal, secular, social democracy to now come and join together to preserve and protect the integrity of the republic.
"This is indeed a moment in our history when all right-thinking people should come together and pool their wisdom, knowledge and experience to defend the core values of our republic", he said.
Rejecting the campaign that the ideas and thought of the first prime mwere not relevant today, he said, "What greater tribute can there be to Nehru than that, over half a century after his passing, the centre stage of Indian politics is reserved for him? That not a moment passes when his ideas are either celebrated or opposed?"