Speaking at the Indian Science Congress centenary session here, he said "complex issues" including those of "genetically modified food or nuclear energy or exploration of outer space cannot be settled by faith, emotion and fear but by structured debate, analysis and enlightenment".
"Scientific approach and understanding of these issues are, therefore, as vital as our core scientific capabilities," the prime minister said.
His remarks come in the wake of controversy over the issue of Bt food products, especially genetically modified brinjal, against which there was a campaign.
The Kudankulam nuclear power project in Tamil Nadu has also witnessed protests over safety concerns.
The prime minister said Indians "as a society, must enhance the spread of what Jawaharlal Nehru used to describe as the scientific temper. Our younger generations must adopt a science-based value-system in order to benefit from what science can offer and to make up for lost time".