How to evaluate the value of one life?

The value varies depending on the context, and it tends to change over time.

For example, the cost of a flood control project is weighed against the value of life and property saved as a result of the project. We don't build a 20 billion dollar project to save one life. (And we don't halt such a project if someone is killed on the job of constructing it.)

A medical insurance policy will often specify a lifetime maximum for certain kinds of insurance payments. You might consider that figure to be the one the company puts on the value of a life.

The disease management industry in the US is one of the leading causes of death, yet relatively little money is spent on reducing the death rate due to medical mistakes. Consequently, you could say the medical profession tends to put a low value on a life.

In the case of the gorilla we have a member of an endangered species - Added value. Who is closely related to humanity - Added value.

On the other hand it was a child - Added value. Who did not know he was putting himself in danger - Reduced blame.

Claiming infinite value leads to all sorts of problems, but so does claiming finite value.

It has infinite value. Plain and simple. Human lives are the most valuable thing in the universe.

The real hard question comes when you must take one to save one.

Live it to its completion!