Piers Morgan started a twitter debate about god. “Atheists can never say what was there before the Big Bang” starts a recent tweet posted by the journalist-turned-television presenter. Morgan then moves to the existence of a higher power. A quick scan of the replies shows that the mere suggestion is enough to raise hackles.

Morgan’s tweet is a “cosmological argument” – one that argues that there must be an ultimate cause or explanation for the existence of the universe and that it must be god.

When focusing on causes, the idea is to question what caused, say, the Big Bang? If science finds that it’s a physical cause, we’ve gone nowhere, for what brought that about? And if the cause is non-physical, it must be supernatural. When focussing on explanation, the question is what explains the sum total of all facts? If it’s a scientific explanation, such as the fundamental laws of nature explaining everything, then what explains those laws? And the argument goes round again. If the explanation is non-scientific, then god isn’t far behind.

I doubt such arguments prove god’s existence for sensible objections abound. For instance, in response to Morgan, scientist (and television presenter) Brian Cox – who, as any fan of his radio show The Infinite Monkey Cage will know, is not philosophy’s biggest fan – nevertheless turns philosophical and suggests that perhaps nothing explains these things.

Another objection to this kind of argument is that god isn’t a good explanation because what would explain god?

Or consider one last objection. We might say that a prior universe was responsible for the Big Bang, and before that one, there was another. And so on, forever. Because this chain of universes has been around forever, the suggestion is that they need no explanation.

Problems with the objections

To each objection there are rejoinders – if there weren’t, philosophers like myself would be doing it wrong.

Can scientific phenomena really have no explanation? Isn’t science based on the idea that all things have discoverable explanations? Even particles popping into existence in the quantum foam have an explanation for their existence (namely, the laws of quantum physics) even if they have no specific cause.

And maybe it’s OK for god’s creation of reality to be inexplicable. Some people – “libertarians” – suggest that people’s free choices have no explanation. If our choices were wholly explained (for example, by our brain activity) there would be no free will. So even if scientific explanations always need explanations, god’s actions don’t.

What about the eternally existing chain of universes? Imagine you stumble across a perfect statue of yourself. Wondering why the hell it’s there, is it really satisfactory if someone says it just happens to have been there for all eternity? I doubt it.

Good arguments needn’t be proofs

The literature on the cosmological argument is vast. It’s an open question whether the crucial premises are true or not. So it isn’t proof of god’s existence. But that doesn’t mean the cosmological argument is a bad argument. To be good, an argument doesn’t have to conclusively and undeniably prove its conclusion. Good reasoning needn’t be impervious to doubt.

Intelligent, well-informed adults can be justified in believing different things. Two physicists might disagree over a correct fundamental physical theory. One might say it’s superstring theory. Another might believe it’s loop quantum gravity. And both can be justified, even though they have the same body of information to hand. Indeed, they can be justified even though at most one of them is right. Being justified in believing something doesn’t mean it has to be true. Sometimes rational trains of thought can lead us astray – such is life.

And it’s not just science. Veteran politicians disagree even though they’re privy to the same information. Politics also shows that non-experts can similarly disagree. People who haven’t waded through all of the available information nevertheless get to have justifiable political views. Liberal democracy is founded on the idea that voters make sensible, justified decisions when they vote. You don’t need to be the West Wing’s fictional Nobel Prize-winning president, Jed Bartlet, in order to justifiably believe that lower business rates could work out well, that railway nationalisation is the way forward, or – in short – justifiably have a political opinion.

New atheism and Brexit

The, often outrageously rude, debate on Morgan’s Twitter feed shows that people tend to want religious arguments to meet some crazily high standard of proof. This is not unusual – it characterises a lot of New Atheist debates. But it’s an unfair burden. Churchgoers aren’t simpering morons just because they can’t prove god exists in the same way that we can prove to anyone that there are an infinite number of prime numbers.

So Morgan may not be telling atheists why they have to believe in god. Rather, he may be making a claim about why he is justified in believing in god. Those things are different. It’s implausible to believe that 140 characters is going to change the mind of every atheist. But if Morgan is just giving us an insight into his own belief structure – claiming only that his faith is justified – then, since the jury is out when it comes to the cosmological argument’s crucial premises, he’s on solid ground.

In the same way that a scientist may believe superstring theory in lieu of conclusive experimental evidence, or how politician Jeremy Corbyn can think that nationalising energy is sensible even though questions remain (for don’t questions always remain?), Morgan can be justified in believing in god.

This lesson isn’t just one for religious debate. The world (and the internet, especially) would be a better place if we worried less about whether someone was wrong and more about whether they’re justified. As new technologies allow for evermore public clashes of views, such as with the often vicious Brexit debate, realising that intellectually sophisticated adults can be justified in believing diametrically opposed things has never been more important.

Nikk Effingham, Senior Lecturer in Philosophy, University of Birmingham.

This article first appeared on The Conversation.