Evolution explains why we're here, and our only purpose is to survive and reproduce

What's right about this

Evolution is a powerful scientific theory, and many Christians, including the geneticist Francis Collins in The Language of God, accept it fully. It explains a great deal about how life developed and why we have the bodies and instincts we do. If someone asks "how did humans come to exist?", evolution is a big part of the answer.

How vs why

But "how did we get here?" and "why are we here?" are different questions. Evolution describes a process. It doesn't tell us whether there's a reason behind the process. Think of a kettle boiling. You can explain it by physics, heat transferring to water molecules. Or you can explain it by purpose: "I'm making tea." Both are true. One doesn't cancel the other. Evolution could be the how, and God the why.

Survival isn't a purpose anyone lives by

It's also worth noticing that almost no one really lives as if survival and reproduction were the whole point. People choose not to have children, sacrifice themselves for strangers, devote their lives to art or truth that brings no reproductive advantage. If evolution were our only purpose, these choices would be failures. Most of us think they're among the noblest things humans do.

Viktor Frankl, who survived Auschwitz, wrote in Man's Search for Meaning that people need a reason to live that goes beyond mere survival. In the camps, those who had a "why" were often better able to endure. A purely biological purpose doesn't satisfy that hunger.

Description isn't prescription

Even if evolution shaped us to want certain things, that doesn't tell us what we ought to do. Philosophers call this the gap between "is" and "ought." Biology describes what happens; it doesn't tell us what's worth living for. To get purpose, you need something more than biology.

Where Christianity comes in

Christianity says we exist because God freely chose to create us, out of love, so that we could know him and share in his goodness. That's compatible with any scientific account of how he did it. And it gives us a purpose that matches what we actually long for: love, meaning and lasting significance (see Why are we here?).

A fair concession

"God's purpose" can't be proven by science, just as "no purpose" can't be. Both are philosophical conclusions drawn from the whole picture.

How to explain this to a friend

A simple example works well with friends: ask why the kettle is boiling. "Because heat makes water molecules move faster" and "because I'm making tea" are both true, and one doesn't cancel the other. Evolution can be the scientific how while God is the why. Then ask whether your friend really lives as if survival and reproduction were the whole point. Almost no one does.

The bottom line

Evolution may explain how we came to be. It is silent on whether there's a reason we exist. And almost no one actually lives as if survival were the point. For more, see Does life have a purpose?