Causal questions are at the heart of science. Yet, cognitive biases and logical fallacies are major sources of error in causal research across all disciplines. For decades, most aspiring young scientists, those in post-graduate training as well as experienced practitioners in continuing education have not been formally trained – as opposed to a mentor-focused approach - in the philosophical foundations of research practice, including causal reasoning. Instead, science education is strongly influenced by the prevailing culture of valuing specialized subject matter knowledge over sound education in the first principles of science. The proposed NeuR3o-LOGIC learning unit will emphasize critical thinking on causal questions, illustrated by examples from the neurosciences at the interface of the gut-brain axis, an ostensive topic that every human being can relate to. Inspired by our experiences of ‘teaching science like we do science’ in the R3 Graduate Science Program and the Johns Hopkins Bloomberg School of Public Health, we approach this complex topic from the angle of sound error analysis. Driven by our commitment to the three ‘R’s of good scientific practice – Rigor, Reproducibility, and Responsibility, which inform the R3 Program’s name – the proposed METER project will put the learner into a position to recognize where science can go wrong in the realm of causation. Supported by tangible research examples at the intersection of the gut microbiome and the nervous system, the NeuR3o-LOGIC unit will provide the learner with opportunities to employ a structured error analysis and reduction approach to make connections between fundamental thinking in logic and epistemology and major public health issues such as autism spectrum disorders and other neurological conditions. The proposed work does complement, yet not overlap with existing and ongoing, federally funded projects of educational scholarship on the effectiveness of R3 Program training in ethical decision making and data science skills (NSF-IGE Award #1955062; R25 Award #R25AI159447; administrative supplement on T32 Award #T32AI007417). While the first project year will be focused on the design, production, progress monitoring, and initial quality improvement within the NeuR3o-LOGIC project team, regular communication with CENTER will ensure the alignment of goals and objectives. Years two and three of the proposed project will be dedicated towards structured and coordinated project evaluation and revision activities in close coordination with CENTER, the steering committee, and the network of METER awardees in a collaborative community of practice.