On the publication of his new book In Defence of the Enlightenment, Tzvetan Todorov tells British philosopher AC Grayling why the Enlightenment must be separated from scientism and cultural chauvinism.

Astronomy, from Copernicus on, has transformed our view of the place of the earth in the heavens. Darwin changed forever our view of the status of humanity. Neuroscience is likely to challenge our very understanding of what it is to be a person.

Calculations based on the trust's figures show the 10 tonnes emitted by a return flight from London to Sydney would be offset by enabling the avoidance of one unwanted birth in a country such as Kenya.

So one African's life is worth the carbon emissions of one flight from London to Sydney? Something tells me the African is not the problem in this equation.

Providing the means for women to avoid an unwanted birth is an admiral pursuit but, really, offsetting the over consumption of people in rich countries to fund it?

Let me start with a socialist axiom … : freedom cannot flourish without equality and equality does not exist without freedom.

While logically and philosophically inseparable, equality and liberty have followed different and even opposed trajectories. For liberalism, freedom in its negative and positive forms is primary. Negative freedom is captured in Hobbes's statement that liberty is the absence of "external impediments". The positive "freedom to", on the other hand, was classically defined by Isaiah Berlin: "I wish my life and decisions to depend on myself, not on external forces of whatever kind … to be the instrument of my own, not of other men's acts of will."

Anarchism, the name given to a struggle for a society characterised by the ability of each actor to have a say in outcomes proportionate to the degree they are affected by them.