Considering the amount of 'debate' that there has been between atheists and people of faith in the last 10 years or so, it's surprising how few genuine encounters there are.

Formal debates happen, certainly. But they tend to be between academics who argue over philosophical, scientific and other technicalities. While these are important, they don't often speak in the language of normal lay people.

There have been popular-level books on both sides of the debate. But these are often released without interaction happening between the authors. Richard Dawkins refuses to debate many Christians, while sadly, some leading Christian voices seem unable to articulate the faith in a way which is convincing enough for atheists to take it seriously.

Thank God, then, for Stephen Colbert and Ricky Gervais.

British actor, writer and comedian Gervais has become one of the most high-profile atheists in the world in recent years. His success, which began with the British The Office and Extras has given him entry into the world of Hollywood where he is a regular on red carpets and as the host of award shows.

He has used this platform to espouse his atheism on a regular basis. His regular tweets mocking belief have been followed up by a series of discussions on news shows. He regularly features in atheist videos. In one, Gervais makes the extraordinary claim that it would be good if parents didn't teach their children any of their metaphysical beliefs until they were 20. "There'd be more atheists and less faithful if you weren't allowed to teach anything, you weren't allowed to mention any Gods or any beliefs or atheism until they were 20... It's strange that we hold onto these medieval beliefs."

Stephen Colbert, one of the biggest names in late night US TV, regularly mentions his faith. Like Gervais, he occasionally uses his platform to espouse his beliefs. Faith is an important part of his life, so he speaks about it on his show and in interviews.

He has argued with some of the most famous atheist voices such as Bill Maher. So when Gervais was a guest on Colbert last night, it was almost inevitable that they got round to talking about God...

Colbert asked Gervias one of the most fundamental questions that we all have to confront at one time or another. "Why is there something instead of nothing?" Gervais seems temporarily floored by it. "That makes no sense at all. That's not the choice at all," he says, dismissing out of hand a question which Heidegger described as "The fundamental question of metaphysics."

Gervais then fires back, "Surely the question is not why, but how?"

Well, not so fast Ricky... The 'how' question is incredibly important and it's one that scientists continue to pursue. But the 'why' question can't be answered by science. It's a different kind of question. "Why is irrelevant," claims Gervais – as if all inquiry into the reasons for the existence of the universe over thousands of years could just be swept away.

He goes on to suggest that he doesn't believe in God because there's no proof for it. "Everything in the universe was once crunched into something smaller than at atom," he then says (correctly citing the scientific consensus). "But you don't know that," fires back Colbert – in a bid to show that 'proof' is too high a standard for Gervais to hold Christians to – if he can't 'prove' what happened at the beginning of the universe. "You're just believing Stephen Hawking and that's a matter of faith in his abilities," carries on Colbert, "you don't know it yourself, you're accepting it because someone told you."

Gervais can't give a direct response, so falls back on the claim that, "science is constantly proved all the time".

Here's the thing. Colbert's aim isn't to undermine science. He's an intelligent guy. He's merely showing how Gervais is holding different standards. He sees no 'proof' of God, therefore he's an atheist – fine. But then he claims there is constant 'proof' in science – when that simply isn't the case. Science weighs the evidence and comes up with the best explanation. Yet, it's really not possible to 'prove' what happened at the beginning of the universe, for example.

As one physicist has put it, "So long as the evidence is consistent with the theory, we consider the theory validated. But it will never be proven."

All that we as Christians ask for from atheists like Gervais is an honest debate. Many of us are passionate about science and its ability to help us explain the world. We believe in evolution, climate change and the rest of the scientific consensus. We think science is the best way of explaining 'how' questions. It's just that we don't believe that science can explain 'why' questions.

Two of our leading entertainers debated this on TV last night and it strikes me that one of them showed up the weaknesses in the other's position. Long may the debate continue...

Follow Andy Walton on Twitter @waltonandy