This is from the Well Spent Journey blog.
Here’s a thought experiment.
Imagine that you’re a healthy, athletic, 20-year-old male. It’s the morning after a thunderstorm, and you’re standing on the banks of a flooded, violently churning river.
You notice an object floating downstream.
As it moves closer, you suddenly realize that this object is a person. The head breaks the surface, and you see a panic-stricken elderly woman gasping for air. You’ve never met her before, but vaguely recognize her as an impoverished widow from a neighboring village.
You look around for help, but there’s no one in sight. You have only seconds to decide whether or not to jump in after her – recognizing that doing so will put your own life in significant peril.
The author continues:
Is it rational for you to risk your life to save this stranger? Is it morally good to do so?
For the Christian, both of these questions can be answered with an emphatic “yes”.
The Christian is called to emulate the example set forth by Jesus, who not only risked, but sacrificed his life for the sake of others. The Christian believes that the soul is eternal, and that one’s existence doesn’t come to an abrupt end with death. Additionally, he can point to the examples of countless Christian martyrs who have willingly sacrificed their own lives.
For the secular humanist, the answers to these questions are much more subjective. When I previously asked 23 self-identifying atheists, “Is it rational for you to risk your life to save a stranger?” only 4 of them responded with an unqualified “yes”.
Biologically speaking, the young man in our scenario has nothing to gain by jumping after the drowning woman. Since she’s poor and elderly, there are no conceivable financial or reproductive advantages involved. Evolutionary biologists often speak of “benefit to the tribe” as a motivation for self-sacrifice…yet the young man’s community would certainly place greater practical value on his life than that of a widow from a neighboring village.
Secular humanists argue that people are capable of making ethical decisions without any deity to serve as Moral Lawgiver. On a day-to-day basis, this is undeniably true. We all have non-religious friends and neighbors who live extremely moral and admirable lives.
In the scenario above, however, secular ethics break down. The secular humanist might recognize, intuitively, that diving into the river is a morally good action. But he has no rational basis for saying so. The young man’s decision is between empathy for a stranger (on the one hand) and utilitarian self-interest & community-interest (on the other).
In the end, there can be no binding moral imperatives in the absence of a Moral Lawgiver. If the young man decides to sit back and watch the woman drown, the secular humanist cannot criticize him. He’s only acting rationally.