Atheist / secularist / Libertarians like to claim that they are basing everything they do on reason.
But this is simply not true
These three groups of people, have basic beliefs that they base their reasoning on. These beliefs from a secular atheist view are called assumptions, but they are beliefs that are held by faith.
These beliefs they say are based on science, but they believe the science is naturalism. Or sometimes they believe that science is consensus.
In other words these three groups secular / atheist / Libertarians hold beliefs / assumptions and these assumptions are held by faith not provable by reservable repeatable experimentation.