Partialism is a flawed view of God that suggests that the three members of the Trinity are each “100 percent God” but not “100 percent of God.” As an analogy, partialism would point out that the Atlantic Ocean is 100 percent water, and the Pacific Ocean is 100 percent water, but the Atlantic Ocean by itself is not 100 percent of all the water that exists. According to partialism, each Person of the Trinity is 100 percent divine in nature, but God is only God when, where, and if all three Persons are unified. Some partialists—but not all—would extend this idea by stating that the Father, Son, and Holy Spirit are each “1/3 of God.”
Complicating the issue are the many different ways to interpret the basic idea of partialism. A partialist might claim God is only God when all three Persons of the Trinity are “together” but also claim these three Persons can never be separated, making the idea practically irrelevant. On the other extreme, a partialist might claim that, when Jesus called out to God during the crucifixion (Matthew 27:46), the Trinity was broken, which is absolutely contrary to scriptural concepts.
So, a particular flavor of partialism can be compatible with Scripture, while another may be incompatible and contradictory to Scripture. Since partialism is fairly obscure and open to such wide interpretation, it is rarely named among the major false views of the Trinity. That being said, certain views of partialism, if not the very idea itself, run counter to most Christian interpretations of the Trinity. For instance, the church father Athanasius, writing about the Council of Nicaea, correctly emphasized the unity of God and indicated that God is “without parts,” but partialism opposes Athanasius’ view. The more insistently a person pursues the idea of partialism, the more likely he is to drift into something theologically incorrect.
Partialism is subject to widely varied applications, making it impossible to declare that all forms of partialism are false or that all forms are true. Still, generally speaking, most interpretations of partialism conflict with well-established interpretations of the Trinity. Any supposed value or insight gained through partialism is minimal, if not trivial. Potential misunderstandings or misapplications, however, could be quite consequential. As a result, partialism is not a concept that should be considered part of Christian orthodoxy.