Immanuel Kant is a philosopher who tried to work out how human beings could be good and kind outside of the exaltations and blandishments of traditional religions.

He was born in 1724, in the Baltic city of Konigsberg, which at that time was part of Prussia and now belongs to Russia, renamed Kaliningrad.

Kant's parents were very modest, his father was a saddle maker.

Kant never had much money, a fact he dealt with cheerfully by living very modestly.

It wasn't until he was in his fifties that he became a fully salaried professor and attained a moderate degree of prosperity.

His family were deeply religious and very strict.

Later in life Kant did not have any conventional religious beliefs,

but he was acutely aware of just how much religion had contributed to his parents' ability to cope with all the hardships of their existence and how useful religion could be in fostering social cohesion and community.

Kant was physically very slight, frail, and anything but good looking, yet he was very sociable and some of his colleagues used to criticize him for going to too many parties.

When eventually he was able to entertain, he had rules about conversation at his table.

At the start of a dinner party he decreed that people should swap stories about what had been happening recently,

then there should be a major phase of reflective discourse in which those present attempted to clarify an important topic,

and finally there should be a closing period of hilarity so that everyone left in a good mood.

He died in 1804 in his eightieth year in Konigsberg, having rarely felt the need to spend any time outside the city in which he was born.

Kant was writing at a highly interesting period in history we now know as The Enlightenment.

In an essay called "What is Enlightenment?" published in 1784, Kant proposed that the identifying feature of his age was its growing secularism.

Intellectually, Kant welcomed the declining belief in Christianity, but in a practical sense he was also alarmed by it.

He was a pessimist about human character and believed that we are by nature intensely prone to corruption.

It was this awareness that led him to formulate what would be his life's project, the desire to replace religious authority with the authority of reason, that is human intelligence.

When it came to religion, Kant summed up his views in a book entitled "Religion within the bounds of reason alone".

Here he argued that although historical religions had all been wrong in the content of what they believed, they had latched onto a great need to promote ethical behavior, a need which still remained.

It was in this context that Kant came up with the idea for which he's perhaps still most famous, what he called the "Categorical Imperative".

This strange sounding term first appeared in a horrendously named work "Groundwork of the metaphysics of morals".

The Categorical Imperative states: What did Kant mean by this this?

This was only a very formal restatement of an idea that's been around for a long time, something we meet within all the main religions.

Kant was offering a handy way of testing the morality of an action by imagining how it would be if it were generally practiced and you were the victim of it.

It might be tempting to filter a few pads of paper from the station recovered at work, it seems like a small thing.

But if everyone did this, the cupboard and society at large would need a lot of guards.

Similarly, if you have an affair and keep it quiet from your partner you might feel that's okay

but the categorical imperative comes down against this because you would then have to embrace the idea that it would be equally okay for your partner to have affairs and not tell you.

The categorical imperative is designed to shift our perspective, to get us to see our own behavior in less immediately personal terms and thereby recognize some of its limitations.

Kant went on to argue that the core idea of the categorical imperative could be stated in another way: This was intended as a replacement for the Christian injunction for universal love, the command to "love one's neighbor."

To treat a person as an end, for Kant meant keeping in view that they had a life of their own in which they were seeking happiness and fulfillment and deserve justice and fair treatment.

The categorical imperative, Kant argued, is the voice of our own rational selves.

It's what we all truly believe when we're thinking sensibly, it's the rule our own intelligence gives us.

Kant extended his thinking about the categorical imperative into the political sphere.

He believed that the central duty of government is to ensure liberty,

but he sensed there was something terribly wrong with the ordinary definition of freedom or liberty, it should not be thought of in libertarian terms as the ability to do just whatever we want.

We are free only when we act in accordance with our own best natures, and we are slaves whenever we are under the rule of our own passions or those of others.

As Kant put it ... So freedom isn't an absence of government, a free society isn't one that allows people more and more opportunity to do whatever they happen to fancy.

It's one that helps everyone become more reasonable.

The good state represents the rational element in us all.

It rules according to a universally valid will under which everyone can be free, so government ideally is the externalized, institutionalized version of the best parts of ourselves.

It might be a bit surprising at first to discover that in 1793, Kant published a major work on beauty and art, "The Critique of Judgment."

It might seem like a bit of a sideline for a thinker otherwise concerned with politics and ethics, but Kant held that his ideas about art and beauty were the cornerstones of his entire philosophy.

As we've been seeing, Kant thought that life involved a constant struggle between our better selves and our passions, between duty and pleasure.

Beauty, Kant especially liked roses, vines, apple trees and birds, delights us in a very special and important way.

It's a reminder of and goad to our better selves, unlike so much else in our lives, our love of beauty is in Kant's word "disinterested," it takes us out of our narrow, selfish concerns but in a charming delightful way without being stern or demanding.

The beauty of nature is a continual, quiet, and insistent reminder of our common universal being.

A pretty flower is just as attractive to the tired farm worker as to the prince.

The graceful flight of a swallow is as lovely to a child as to the most learned professor.

For Kant, the role of art is to embody the most important ethical ideas.

It's a natural extension of philosophy.

Kant held that we needed to have art continually before us, so as to benefit from vivid illustrations and memorable symbols of good behavior and thereby keep the wayward parts of ourselves in check.

Kant's books were dense, abstract, and highly intellectual, but in them he sketched a very important project that remains crucial to this day.

He wanted to understand how the better, more reasonable parts of our natures could be strengthened so as to reliably win out over our inbuilt weaknesses and selfishness.

As Kant saw it, he was engaged in the task of developing a secular, rational version of what religions had, very imperfectly, always attempted to do, help us to be good.