That’s counter-intuitive but potentially profound. After all, reality is complex. There’s something fishy about the too-simple explanation or the too-pat story. Still, when it comes to figuring out what truth is, inconsistency is more often an alarm bell than a confirmation we’re on the right track. As the fault-lines between our various truth commitments yawn wider, something’s gotta give. Becoming aware of those tensions can be an uncomfortable experience, but it’s also one of our most reliable routes to new knowledge.

Inconsistencies between the two pictures become harder to ignore. We will have to choose.

If both things can’t be true, where have I gone wrong? Which one is closer to reality? This is increasingly the situation for a key question of our time: what does it mean to be human?

In February, the magazine New Philosopher published a joint edition with the New York Times, on the theme “Being Human: All About Us.” It features articles with such titles as “Doing Away With Death” and “Defining Ourselves.” The blurb for the issue reads: “What makes us fully human is the ability, and the willingness, to walk a mile in another’s shoes. We may be born Homo sapiens … but we must become a human being – an ongoing task that requires effort, education, and empathy.”

That sounds all rather nice, apart from the fact that it’s a simple assertion. Who says that humanness is something we grow into? How do we know? The definition of humanity in 21st-century cultures is malleable, up for grabs. And few questions have more serious ramifications for our life together than this one.

Secular Westerners live with two competing pictures of themselves. One is the deep moral intuition that every person has value and dignity, which historians trace back to the Judeo-Christian conviction that we are all created in the image of God: loved, purposefully made, deserving of respect – regardless.

The other gives primacy to our existence as semi-autonomous collections of atoms, machines optimised for survival and reproduction. In this picture, the non-material elements of our lives – our consciousness, our loves, our yearning for transcendence – are a bit suspect, maybe even illusory. Utility and pleasure become the key measures of human life.

As a society, we try to force these two puzzle pieces together, and refuse to notice they’re quite different shapes. As we navigate questions like surrogacy, abortion, euthanasia and transhumanism, the inconsistencies between the two pictures will become harder to ignore. We will have to choose.

When moral intuitions and moral reasoning clash, interesting things happen. Last year, we at CPX interviewed an early-modern historian, Sarah Irving-Stonebraker, for our Life & Faith podcast. Now at Western Sydney University, Sarah studied at Cambridge and then secured a fellowship at Oxford. Her life was going exactly to plan – but she says she found her success unsatisfying.

While at Oxford, Sarah decided to hear atheist philosopher Peter Singer, who was speaking on ethics and the duty we owe to other people, and whether human lives have any intrinsic value.

“I went to these lectures really excited,” Sarah explains, “and I was expecting that, as an atheist, I’d be hearing exactly the sort of ethics that I subscribed to. But actually, what I heard floored me.”

Over a period of reflection and searching, Sarah came to the conclusion that her atheism could not sustain her moral beliefs

Sarah was deeply committed to a humanist ethic, to a bedrock moral intuition about the inalienability of human value. Singer, who takes widely accepted positions on human life and morality and reasons them through to their logical conclusions, has argued for ideas such as “post-birth abortion” – there is no meaningful difference, for some time, between a baby in the womb and one outside of it, so why treat them differently? – which almost all defenders of current abortion practices find repugnant.

Ironically, it was her encounter with Singer’s ideas that kickstarted Sarah’s journey from atheism to Christian faith. Over a period of reflection and searching, she came to the conclusion that her atheism could not sustain her moral beliefs, and those beliefs led her to conclude that the Christian picture of reality was the accurate one.

If she’s right – if the Bible is telling the truth about God and humanity, and how life is meant to be lived – then there will always be what the apologist Os Guinness calls an “inescapable tension and dynamic conflict inherent in unbelief.” We humans can never entirely get away from God’s truth: either we will have to live in ways inconsistent with our stated beliefs (such as treating human lives as always valuable while denying the basis for that value), or we will act in line with our beliefs and results will be ultimately unacceptable.

Of course, Christians are plenty inconsistent too. In an interview with CPX in 2017, the Catholic philosopher Charles Taylor, when asked about secular humanism and the problem of grounding human value absent a belief in God, offered a poignant personal reflection. “From a Christian point of view,” he mused, “it’s a great gift to be able to see the humanity in every human being. I remember once a film I saw about Mother Teresa and people [ask], ‘ These people, they’re dirty and they’re sick and they’re lousy, and how can you go and help them?!’ And she said, ‘They’re made in the image of God.’ And then I realised: I could have given that answer. But the difference is she really feels that… wow. That is a tremendous gift.”

Given a healthy dose of humility, it’s in that tension between what we say we believe and how we live – and in the tension between our beliefs and beliefs of those around us – that we will find room for honest conversation, and growth.

Natasha Moore is a Research Fellow at the Centre for Public Christianity. For more, visit publicchristianity.org