"This is the generation of the great LEVIATHAN, or rather, to speak more reverently of that mortal god, to which we own under the immortal God, our peace and defense." -Thomas Hobbes: Leviathan
(1) The “Felt-Needs” Motivation
If you’ve hung around charismatic or pentecostal circles long enough, then you’ll know what the phrase “felt-needs” refers to the needs which we deeply feel or materially require. It can range from something as mundane as God answering a prayer for a job to God granting a major military victory over one’s foes.
This is probably one of the most common reasons for conversion from pre-modern Christendom to all areas outside of first world nations. One of the things one learns from studying Church history is how universal this motivation was. We might be tempted to condemn such prosperity Gospel thinking as “pagan” and “materialistic”, however it was not only pagan priests who counselled their kings to convert to Christianity because the Christian God brought material benefits, no less than the medieval ecclesiastical historian St Bede himself have praised such counsel as “prudent words” (much to the disappointment of a 19th century commentator).
Of course as long as Christ remains the healer not only of souls but the flesh, this motivation will last as long as this world itself. This motivation is surprisingly persistent even in our so-called modern age as can be seen in Asian, African and Latin American Christianities and among the economically disenfranchised in first world nations. It is only we who live in the first-world, who enjoy the comforts of modern political and economic security, who are embarrassed by such a crudely materialistic, or “pagan”, motivation. However, this motivation is simply a testament to the conviction of the Gospel that God doesn’t only move mental furniture, he moves actual mountains itself.
(2) The “It’s Historically True” Motivation
This approach became very popular from the 17th century onwards, particularly in the Anglosphere. With the Protestant Reformation and the scientific revolution the evidential basis for the Christian faith demanded fresh and new articulation. The Protestants, unlike the Roman Catholics, could not say that they believed the Bible or the Gospel simply because an infallible Church today tells them that it’s true. A different reason was required and to that end they turn to reason and historical evidences to demonstrate the historical reliability of the Bible and the truths of the Gospel.
Discussions on Christian evidences mutually influenced the development of the law of evidence in the Anglosphere legal system. The image which the British Protestants thinkers invoked was that of the court room. They argued that what we need was not “infallible” proof or certainty but probable or “morally certain” proofs, “proofs beyond a reasonable doubt”, sufficient for decision and action. They argued that people have invested in less than infallibly certain ventures, condemn people as guilty and send them to prison for life based on merely probable evidence. If we could lock someone up for life based on such probable evidence, why couldn’t we bind ourself to Christ on a similar basis?
Thus, the argument goes, there are good and sufficient historical evidence for the veracity of the Gospel accounts and the reliability of the Bible. Such evidences provide for “proofs beyond a reasonable doubt” for us to believe that Christ indeed rose from the dead and was God’s only begotten Son. This is a sufficient basis for us to put our faith in him.
This approach survives to this day in mostly Protestant and Evangelical apologetics like Lee Strobel’s books on the Case for Christianity. I myself began my Christian faith with his books and “legal” arguments for the Christian faith. This sort of motivation to believe in Christianity is something which is much more common in the literati or educated middle class circles who possess the academic capacity to grasp such arguments and proofs.
(3) The Subjective “Existential/Romantic” Motivation
This is probably the rarest motivation for it only concerns a subsection of the literati. This motivation are mostly for people who are materially secure, or indifferent towards material concerns, and as such aren’t moved by (1), but are too romantic or existential to be moved by anything so rational as (2). Thus, sceptical of the possibility of the material world or reason in making evident Christian grace, they simply make a highly intense subjective decision to believe in it.
This can either take a “Barthian/Kierkegaardian” form whereby one makes an existential leap of faith or decision to believe in Christ in the face of a world which obscures his presence, or it can take a “romantic” form whereby one’s aesthetic sensibilities are titillated by some “beautiful” or elegant worldview, picture, system, or even “vision” of the Christian life presented by literary works or philosophy. Alternatively it can also take a Calvinistic form whereby some mysterious movements of the Holy Ghost in one’s soul moves one to believe in Christ. They are all in the same category simply because they are all essentially “subjective” existential or romantic reasons for believing in the faith, reasons rooted in something which goes on in one’s soul rather than caused by the “objective” world.
Naturally real life is a lot more complicated than these three categories and most of us would probably believe for a combination of these three reasons. However I think it is important to be aware of the sort of environmental and cultural circumstances which most stimulates the three reasons.