Religion is on the decline, with nearly half of us in England and Wales – and more than half in Scotland – saying we have no religion. But is faith also on the wane? Religion and faith are often treated as synonymous. But as an atheist I am frequently told that I must have faith too, since I can no more prove that God does not exist than theists can prove he does.

To see if faith is weakening we have to go beneath the apparent mathematical precision of surveys to the vaguer ideas they attempt to quantify. Even religiosity is hard to measure. Around half of us may not be “religious” but other surveys tend to show that a fifth of us at most – probably less – are prepared to call ourselves atheists. The remainder reject organised religion with its hard-to-swallow doctrines and inconvenient rules, but they retain a belief in a spiritual dimension that is more religious than it is secular.

If “religious” is a slippery concept, “faith” is even greasier. In some of its senses, we certainly do see plenty of faith outside organised religion. If faith is a kind of passionate conviction, for example, then look no further than the zealous breed of atheist who not only personally rejects religion, but also sees it as an offence to human rationality. Like the religious, their core belief becomes the centre of their lives, their moral compass, their blueprint for a better world.

Faith can also provide the godless with a source of salvation that is based more on hope than experience. Reason, for example, is vitally important, but mainly because, like democracy, it is only better than the alternatives. Nothing is more powerful for helping us to understand the world accurately. But when we use reason to try to move from understanding to managing and changing, experience tells us we often go horribly wrong. From central state socialism to failed “scientific” diets via the excesses of industrial agriculture, an over-abundance of faith in the power of rational planning has too often left us in a terrible mess.

The claim that non-believers have faith is most credible when applied to the meaning and value we place on life. Without religion, we live in a world that is, from an objective point of view, devoid of all purpose. Even the biological struggle for survival is a kind of cosmic accident about which the universe itself is indifferent. And yet we find value, in some sense even create it, giving a reason for living that nothing or no one else can give us.

So if faith is some kind of belief not fully warranted by reason and evidence, then, yes, the non-religious have it too. However, it would be a mistake to see this as proof of the equal importance of faith to everyone. The key factor is not whether or not we have faith of some kind, but in how central it is to how we live.

This is most evident when you probe the old canard that atheism is a faith position because you cannot prove God does not exist. This makes the mistake of assuming that everything that cannot be 100% proven is equally unproven, which is patently false. Atheists do not believe in God because they see no good evidence that such a deity exists. This falls short of full proof but it is fundamentally an evidence-based position. Many theists, however, believe that there is God while fully accepting that there is an absence of evidence for his existence. Indeed, Jesus said that those who believe without evidence have a purer faith than those, like Thomas, who demanded proof. “Blessed are they that have not seen, and yet have believed,” reports John’s Gospel.

Given that historically faith has been seen as a distinctively religious virtue that non-believers – ye of little of faith – lack, it is curious that so many now want to attribute faith to us heathens. I think this is a sign of a lack of confidence among many religious believers who are aware that their beliefs seem increasingly out of place in the modern, scientific world and are therefore keen to show that, in fact, we’re all in the same boat of belief. If everyone needs faith, then religious belief requires no special justification when, actually, that is precisely what it does need.

What we all need is not best described as faith. It is simply more than can be proven by logic and science. We need to believe in things that are not entirely justified by reason, but that does not require us to embrace creeds that reason tells against. The non-religious do not find meaning, purpose and value by taking a leap into the unknown and transcendental. We find it in the beauty and joy of life, and in the empathy that makes us see value in the lives of others too. These things are not facts captured by fundamental physics but nor are they religious mysteries to be taken on faith. What grounds us ethically can be found entirely on the literal ground on which we live.