Abstract. We argue that reconnecting science and spirituality yields the best rational understanding of the world. Spirituality is seen as the core of many religions. Distinctions are drawn between science and scientism and between spirituality and religion. A historical analysis provides a partial explanation of scientists' aversion to religion. A thought experiment illustrates that spirituality could not only be a legitimate research topic of science but also inform science by offering certain insights. Specifically, science could and should more freely study spirituality in its beneficial impact on individuals' attempts to attain personal wholeness, overcome substance abuse, achieve a more communal society, and safeguard the environment.