For many Buddhist seekers in the West, doubt, particularly about kamma (karma), rebirth, and the various planes of existence (heavenly and hell realms. etc) mentioned in the texts, is one of the biggest hindrances standing between them and the benefits of practice.
As someone who was once a hard-lined atheist, I was skeptical about these notions as well, but I’ve since come to learn that the seemingly irrational parts of Buddhism don’t really matter much, and can be easily interpreted in a simple yet accurate way.
Kamma is a way to describe the causes and effects that naturally arise from our volitional activities. Each action results in an immediate (macro) or subtle (micro) reaction that effects our experience within our environments.
Rebirth is the recycling of our elemental aggregates (khandhas) into a new life form. There’s nothing supernatural about this process, and no souls or anything magical are being passed. This is very much aligns with the law of conservation of energy.
And the heavenly and hell realms described in the texts aren’t like those proclaimed by the Abrahmic scriptures. “Heaven” and “hell” in Buddhism are temporary states—the conditions of which are the byproduct of its inhabitants, similar to pleasant or hostile conditions that are created by the inhabitants of a country.