If you ask anyone how many persons there are in the Trinity, they will likely tell you there are three. This is obvious- the very word “Trinity” comes from ‘Tri’=three, combined with ‘unity’, meaning three in unity. Three persons, of one essence, as the classical formulation goes.
Sadly though, if we actually take the time to examine how many persons many so-called trinitarians believe in, we will quickly see that there is an extra person afoot. This is because many theologians who have succumbed to the lies of semi-modalism have accepted the Trinity itself as a fourth person. These people take the one essence, or divine nature common to the three real persons of the Trinity and imagine it to be a person itself. Another variation of this is to simply imagine that the group of three persons is a single person. By personifying either the group of persons or the divine nature, these false teachers have craftily introduced a fourth person into the Trinity.
Most of the patrons of this error hold their belief in semi-secret. They clearly think of the Trinity as a person in itself. They call it the ‘one God’ (who is actually the person of the Father, see: https://nicenefaith.wordpress.com/2017/03/08/i-believe-in-one-god-the-father-almighty/), the “triune god”, and “god the Trinity”. They worship this person, pray to this person, and constantly expose their belief that this person is a person by using explicitly personal pronouns. When they speak of the “triune god” or “god the Trinity” they always call him “he” and “you”, not “it”, or they”, as we would use to speak of the divine nature or the group of persons together, respectively.
A few of these false teachers, like Cornelius Van Til, have even come out and admitted their belief in a fourth person openly, such as when he wrote:
“… It is sometimes asserted that we can prove to men that we are not asserting anything that they ought to consider irrational, inasmuch as we say that God is one in essence and three in person. We therefore claim that we have not asserted unity and trinity of exactly the same thing.
Yet this is not the whole truth of the matter. We do assert that God, that is, the whole Godhead, is one person…. In other words, we are bound to maintain the identity of the attributes of God with the being of God in order to avoid the specter of brute fact.”
While we must loath Van Til’s heresy, his honesty is praiseworthy. Most such semi-modalists will vehemently deny that they believe the Trinity is a person if asked. Of course, the only difference between their view and Van Til’s conceptually is that they deny the term “person” to the Trinity while clearly treating it as such, while Van Til was honest enough to come out and say what he really thought.
We must recognise this problem. Many people have fallen into thinking in these ways by mistake, not realising that they had traded in their belief in the true Trinity of scripture for a false Trinity of man’s imagination, with four persons instead of three. There is a world of difference between having accidentally having fallen into thinking about these things in a way that is mistaken and having consciously rejected the true doctrine of the Trinity in favor of a false one. Many genuine Christians have temporarily fallen into mistakenly thinking of the Trinity wrongly. Each person must take heed, lest he be deceived, and whoever has been deceived must repent and embrace the truth. It is not the part of true Christians to never err, for all do; rather it is the part of true Christians to repent when they do. Therefore let those who have erred in this respect repent, and embrace the truth.