Children acquire knowledge through direct personal experience and exploration in both the scientific and religious domains; however, they also acquire knowledge indirectly through the testimony of others. Indeed, testimony is especially important when acquiring knowledge in domains where first-hand experience is limited or impossible, such as ordinarily unobservable scientific (e.g., viruses such as COVID-19) and religious phenomena (e.g., God). In this talk, I focus on individual and developmental differences in children's ability to make ontological judgments based on environmental and cultural influences such as religious and scientific exposure. I present findings from children growing up in the United States, China, and Iran, and highlight the role of community consensus in children’s use of parental testimony when determining the existence of things they cannot readily see for themselves.