Many philosophers and logicians have contemplated the relationship between ontology and logic. The author of this paper, working within a Bolzanoan-Husserlian tradition of studying both ontology and logic, considers ontology as the science of the most general features of beings and the most general relations among them. He considers logic as the science concerning the most general statements of all (natural or artificial) languages and the most general relations among them from an inferential point of view. It is possible to see logic in a broader sense as the science of all kinds of relations among all kinds of entities, acts, and processes stating some (objective, subjective, artificial, or conventional) reality. These entities, acts, and processes are not individual, rather, they are idealized, such that their universals may be instantiated at all times and in all places. In formal ontology we search for the properties of those structures of the reality that are formally similar. So we may find some formal truths applying to all things and/or properties and/or processes in different areas of objective/subjective/fictional reality.Surveying briefly the most important relations of logic and ontology in both analytic and phenomenological traditions, the author focuses on this central point: If reality is one as the unity of more or less interconnected and interactive beings of all physical, nonphysical and artificial types, the system of inference too may be one as the unity of more or less interconnected statements of all natural and artificial types. The universal system of inference may be divided into several relatively separate subsystems (having a more or less degree of connection) just as the unified reality has divided into several relatively separate fields (having a more or less degree of connection and interaction). According to such a model for corresponding realities and sciences within the unified reality and the unified science, the author assumes the possibility of beginning to construct both the comprehensive system of reference and the comprehensive formal ontology, both covering all possible members of their own field and being parallel and correspondent to each other, a long-run work, of course, very difficult to do.