History clearly establishes that the open market assigns substantial value to human life. We just happen to have outlawed trading in it. Human life has been deemed worthless by force of law.

Less facetiously, you're committing a semantic error.

Some people will pay a great deal to have a baby. Some will pay to abort their baby.

What value something has is totally dependent on who is valuing it.

More formally, it's the Law of Supply and Demand.

It can be empirically observed that human lives are not assigned much value when choosing to start a war.