I can provide you with some examples of scientific theories that have been subject to ongoing debates or skepticism among scientists, including some atheists. It's important to note that scientific theories are continually tested and refined based on new evidence, so disagreements and revisions are a natural part of the scientific process. Here are a few examples:
Multiverse Theory: Some scientists and atheists have reservations about the multiverse hypothesis, which suggests the existence of multiple universes beyond our observable universe. Critics argue that it falls outside the realm of empirical testing and lacks direct evidence.
String Theory: While string theory is a well-known framework attempting to unify quantum mechanics and general relativity, it remains highly speculative and lacks experimental verification. As a result, some scientists, including atheists, question its scientific status and view it as more of a mathematical construct.
Consciousness and the "Hard Problem": The nature of consciousness and its origins are still a subject of intense debate. Although there are various scientific theories and models attempting to explain consciousness, some atheists and scientists remain skeptical about the current explanations and believe that future research will lead to a more comprehensive understanding.
Origin of Life: While scientists have made significant progress in understanding the mechanisms of evolution and the development of life on Earth, the exact origins of life itself are still not fully understood. The specific processes and conditions that led to the emergence of life from non-living matter are areas of ongoing research and debate.
It's important to remember that skepticism and critical thinking are fundamental aspects of science. Scientific theories are always subject to scrutiny, and if new evidence emerges that contradicts or challenges a theory, it can be revised or even discarded in favor of a better explanation.