The continuing legacy of the Enlightenment period constitutes one of the most creative strands in the fabric of Western civilisation. While some prominent ideas of the Enlightenment were misappropriated to justify odious events, such as the Terror in France and later colonisation, it also bestowed to future generations an important intellectual legacy.

A heterogeneous discourse, the European Enlightenment was stimulated by contact with the great non-European civilisations of China, India and Russia. It grew out of the Renaissance, itself essentially a rediscovery, re-evaluation and extension of scientific and cultural traditions of classical antiquity.

At the core of these traditions, in all of their immense complexity, was the principle of seeking truth - truth about the nature of the cosmos, truth about the fundamental nature of the human race, truth about the organisation of society. Truth discovered through a commitment to empirical research, based on careful observation and the logical analysis of verifiable facts.

Jones acted in the knowledge that a concerted campaign in the mainstream media will often overwhelm positions based on science, evidence and reason. This has been made abundantly clear in the climate change debate. Public debate in Australia (and elsewhere) is now increasingly dominated by often unsubstantiated positions devoid of empirical basis.

Other traditions have always existed. The history of Western society has been marked by periodic swings of the pendulum. There were periods when the spirit of inquiry has been in the ascendant, as well as long centuries when this spirit has been eclipsed and replaced by faith in religious authority, dogma or unsubstantiated personal beliefs. It appears we are witnessing another such swing of the pendulum.

As did Jones, Coalition Senator Cory Bernardi recently asserted on Q&A that climate change is not influenced by human activity. Although every national scientific body in the world, including the Australian Academy of Science, appears to be of the same accord, Bernardi insists there is no consensus within the scientific community.

Bernardi's arguments draw heavily on his personal beliefs. Later on the Q&A program, he referred to his commitment to protecting ''Western values'' that he asserted were based on the Judaeo-Christian tradition. Bernardi extolled the virtues of reciprocity. He inferred that reciprocity concept was unique to the Christian ethic, which in turn constituted the very foundation of Western civilisation and the Western values system.

He might have convinced some viewers but his assertions would not have stood up to even modest interrogation. The concept of reciprocity is central to most religions and ethical systems that have survived through time - if only for the reason that it is critical to a harmonious, functioning society.

The role of secularism was another core value of the Enlightenment. In a functioning democratic society, tolerance of different religious beliefs sits comfortably alongside a commitment to science and evidence-based public policy. Bernardi is able to practise his faith in Australia - and Ed Husic his - because we live in a secular, rational society. An equally rational approach should inform our environmental policy.

If public figures in a secular society have a values system based on faith, they should not hide from it. There is much beauty, wisdom and peace to be found in the scriptures. Personal values that inform public policy, however, should be considered alongside a profound reflection about the human condition, a dispassionate study of history and rational thinking.

To claim an ethical and intellectual tradition supposedly common to Western nations has come from a single source is intellectually unsound. So far as a common philosophical or ethical tradition exists, Western thinking is the product of a continually evolving sum of a vast range of influences.

Christian teachings have made an enormous contribution to the civilisation of the West but it also owes as much to classical Greece and Rome - in turn deeply influenced by Egypt, Persian as the other ancient societies of the Middle East, the pre-Christian Celts and Germans - and to the brilliant civilisation of mediaeval Islam. Conservative champions of Western values would benefit greatly from some knowledge of history.

Bernardi has apparently written a book, The Conservative Revolution, that explains how the ''pillars of Western civilisation'' are ''under threat''. Its integrity may unwittingly prove its underlying thesis.

Science, rationality and empiricism, once pillars of political discourse in Western democracies, have been weakened of late. Unfortunately, the instincts of most modern politicians often militate against a necessary resistance to this unfortunate tendency.

On issues of enduring importance, strong political movements must occasionally sacrifice political ground over the short term to win the long game. Those who have sided with populist, unsubstantiated personal positions on climate change in recent years will be judged poorly in the future.

A public naturally resistant to change will be disinclined to support action on climate change until all doubt is removed. Conservatives have successfully cultivated doubt that action is necessary, and have benefited politically.

Labor has a legacy to protect in the immediate period - a task that will be made easier if it grasps every opportunity to express indignation at the intellectually weak positions of Jones, Bernardi and many of their conservative allies.

We must fight to ensure empiricism remains central to policymaking and political discourse. To do so would benefit the national interest. It would also protect a critical tenet of the Enlightenment: the role science and reason plays in our understanding of the world.

Andrew Hunter is chairman of the Australian Fabians.