What is Apologetics?

Apologetics is the verbal defense of the Faith, for example by dispelling inaccurate stereotypes or by re-presenting doctrine in language that is more accessible to non-believers. The goal of apologetics is to persuasively answer honest objections that keep people from faith in Jesus Christ. Scripture encourages each believer to be an apologist:
[But] in your hearts regard Christ the Lord as holy, always being prepared to make a defense to anyone who asks you for a reason for the hope that is in you; yet do it with gentleness and respect, having a good conscience, so that, when you are slandered, those who revile your good behavior in Christ may be put to shame. (1 Peter 3:15-16)
Apologetics may be contrasted with polemics. which refers to the practice of challenging and refuting doctrinal errors within the same belief system (or religion). Apologetics, therefore, may be viewed as dialogue to defend Christianity to non-Christians and polemics as dialogue internal to Christianity to refute error or provide correctives.
There are many different ways to approach apologetics, most of which are outlined below.

Methods

Classical
"The classical method is an approach that begins by employing natural theology to establish theism as the correct worldview. After God's existence has thus been shown, the classical method moves to a presentation of the historical evidences for the deity of Christ, the trustworthiness of the Scripture, etc., to show that Christianity is the best version of theism, as opposed to, say, Judaism or Islam. This school is called the classical method because it is assumed that this is the method used by the most prominent apologists of earlier centuries."
Contemporary classical apologetic works include William Lane Craig, Reasonable Faith; R.C. Sproul, Classical Apologetics;Norman Geisler, When Skeptics Ask; Stephen T. Davis, God, Reason, and Theistic Proofs; and Richard Swinburne.

Evidential
"The evidential method has much in common with the classical method except in solving the issue concerning the value of miracles as evidence. Evidentialism as a apologetic method may be characterized as the one-step approach. Miracles do not presuppose God's existence (as most contemporary classical apologists assert) but can serve as one sort of evidence for God. This method is fairly eclectic in its use of various positive evidences and negative critiques, utilizing both philosophical and historical arguments. Yet it tends to focus chiefly on the legitimacy of accumulating various historical and other inductive arguments for the truth of Christianity." Proponents of this school include: Gary Habermas, In Defense of Miracles and John Warwick Montgomery, Evidence For Faith: Deciding the God Question.

Cumulative case
"The term cumulative case is used by apologists in ways different than we are using it in this context, but Basil Mitchell, an early proponent of this view, gave this method that name, and so will wil use it here. The careful reader will no doubt note that this method belongs to the same broad family of methods as does the evidential (and perhaps classical) method. However, it will also be apparent that as an argumentative strategy, the cumulative case method has something distinctive to offer. Indeed, this approach to apologetics arose because of the dissatisfaction that some philosophers had with these other evidential-type methods (i.e., the first two of the Big Four)."

Presuppositional
"Due to the noetic effects of sin presuppositionalists usually hold that there is not enough common ground between believers and unbelievers that would allow followers of the prior three methods to accomplish their goals. The apologist must simply presuppose the truth of Christianity as the proper starting point in apologetics. Here the Christian revelation in the Scriptures is the framework through which all experience is interpreted and all truth is known. Various evidences and arguments can be advanced for the truth of Christianity, but these at least implicitly presuppose premises that can be true only if Christianity is true. Presuppositionalist attempt, then, to argue transcendentally. That is, they argue that all meaning and thought - indeed, every fact - logically presupposes the God of the Scriptures."

Reformed epistemology
"Since the Enlightenment, Clark says, there has been a demand to expose all of our beliefs to the searching criticism of reason. (...). We are told that if a belief is unsupported by evidence of some kind, it is irrational to believe it. Reformed epistemology challenges this evidentialist epistemological assumption. Those who advocate this view hold that it is perfectly reasonable for a person to believe many things without evidence. Most strikingly, they argue that belief in God does not require the support of evidence or argument in order for it to be rational. The Reformed epistemology apologist will not necessarily eschew making positive arguments in defense of Christianity, but will argue that such arguments are not necessary for rational faith. If Calvin is right that human beings are born with an innate sensus divintatus (sense of the divine), then people may rightly and rationally come to have a belief in God immediately without the aid of evidence." Proponents of this view would include Kelly James Clark, Alvin Plantiga, Nicholas Wolterstorff, George Mavrodes, and William Alson.

Classic Heresies

Montanism:

Montanism was an early heresy. The movement was begun by Montanus in the second century, shortly after Montanus' conversion to Christianity. He claimed to have received a series of direct revelations from the Holy Spirit, or the paraklete, and was joined by two women, Prisca and Maximilla. His teachings spread from his native Phrygia, where he proclaimed the village of Pepuza as the site of the New Jerusalem and threatened the church hierarchy. The beliefs of Montanism included the belief that the Trinity consisted of only a single person, similar to Sabellianism. Although the mainstream Christian church prevailed against Montanism within a few generations, inscriptions in the Tembris valley of northern Phrygia, dated between 249 and 279, openly proclaim their allegiance to Montanism. This sect persisted into the eighth century.
The most widely known Montanist was undoubtedy Tertullian, the early Church Father who coined the term "Trinity" but who later rejected Christian orthodoxy.





Ebionitism:

Ebionitism was an early heresy. The Ebionites were a first century Jewish-Christian sect. They emphasized Jewish law and rejected the teachings of the Apostle Paul. Most considered Jesus to be a man, not God.





Eutychianism:

Eutychianism was an early heresy which maintained that Jesus Christ was of one nature only.
The heresy was named after Eutyches of Constantinople, who tried in the year 433 to make the 12 Anathemas of Cyril of Alexandria the standard of orthodoxy and do away with the "inspired man" Christology of Antioch. Another goal was to make Alexandria, instead of Constantinople, the second most powerful see in Christendom (next to Rome).
The view of Eutyches was that Christ had only one nature - a confused mixture of human and divine. Eutycianism is also knownas monophysitism from monos (single) and physis (nature). It assumes that Christ can have only one nature, which is a mixture of divine nature and human natures, such that the human becomes divine and the divine human. This confuses both Christ’s true humanity and his true deity. The view was officially deemed heresy by the Council of Chalcedon in 451 CE.





Gnosticism:

Gnosticism is a heresy which is made up of a diverse set of beliefs. It is the teaching based on the idea of gnosis (a Koine Greek word meaning "secret knowledge"), or knowledge of transcendence arrived at by way of internal, intuitive means. While Gnosticism thus relies on personal religious experience as its primary authority, early "Christian" Gnostics did adopt their own versions of authoritative Scriptures, such as those found at Nag Hammadi in Egypt.





Marcionism:

Marcionism was an early heresy led by Marcion, who proposed the first canon of Christian texts. The proposed canon consisted of the Gospel of Luke and several of Paul's epistles; however, Marcion edited the writings by deleting any references that appeared to approve of the Old Testament and the creator God of the Jews. Marcionism thus rejected the Old Testament God, claiming that Jesus represented the true sovereign God who was different from the God of the Hebrew people.
Marcion's proposal for a "New Testament" helped to spur others to respond with other canons that retained the Hebrew scriptures and did not reject Christianity's Jewish heritage. Athanasius, in response to Marcionism, recommended that the Church approve the 27 books which comprise the Christian New Testament.



Subordinationism:
Subordinationism is a heretical view that God the Son and God the Holy Spirit are not merely relationally subordinate to God the Father, but also subordinate in nature and being. In other words, this view maintains that, within the Trinity, the Son and the Spirit are ontologically inferior to the Father. To the contrary, orthodox doctrine maintains that although there is no autonomous Person of the Trinity, none who is God apart from any other Person, yet each Person is autotheos ("αυτοθεος" -God in and of himself).



Modalism:
Modalism, also called Sabellianism, is the unorthodox belief tat God is one person who has revealed himself in three forms or modes in contrast to the Trinitarian doctrine where God is one being eternally existing in three persons. According to Modalism, during the incarnation, Jesus was simply God acting in one mode or role, and the Holy Spirit at Pentecost was God acting in a different mode. Thus, God does not exist as the Father, Son, and Holy Spirit at the same time. Rather, He is one person and has merely manifested himself in these three modes at various times. Modalism thus denies the basic distinctiveness and coexistence of the three persons of the Trinity.
Modalism was condemned by Tertullian, (c. 213, Tertullian Against Praxeas 1, in Ante Nicene Fathers, vol. 3). Also known as Sabellianism, it was condemned as heresy by Dionysius, bishop of Rome (c. 262).
Modalism is probably the most common theological error concerning the nature of God (i.e., who God is). "Present day groups that hold to forms of this error are the United Pentecostal and United Apostolic Churches. They deny the Trinity, teach that the name of God is Jesus... modalist churches often accuse Trinitarians of teaching three gods. This is not what the Trinity is. The correct teaching of the Trinity is one God in three eternal coexistent persons: The Father, the Son, and the Holy Spirit."