Thirdly, one shows that one’s own position is not to be accepted as something from outside, which is thrown at one’s head – this is not good apologetics, throwing stones – but that Christianity is the fulfillment of what is, as longing and desire, in paganism. (This is) the way in which I work that out in all my systematic theology which I call, consciously, an apologetic form of theology: the relationship or the correlation between question and answer. Only if Christianity answers the existential question in the pagan mind can Christianity be accepted and understood.
Now these three steps – first a common ground without which no conversation is possible at all; second, the defects of the object of the apologetic; third, the belief that one’s own position is the fulfillment of what, as longing and desire, is in the other one: this is good apologetics and this you must do whenever you work apologetically, and I cannot imagine any conversation or any sermon which you will ever give in which the apologetic element is not present, in which you do not answer questions, answer to accusations, to criticism, implicitly or explicitly.
Now there is one danger in apologetics: that the common ground is overemphasized over against the differences. And if this is done, then you certainly do not throw stones at the heads of the others; but you don’t give him anything either: you accept him as he is. This is not the purpose either. So you must find a way between these two forms: the one, the wrong way of preaching and teaching Christianity, is: throwing undigestible objects at the other one, which he cannot receive, as the human being cannot receive stones or bullets; the other, that you don’t tell him anything he didn’t know already. And that is often the way in which liberal theology acted, while the other is the way fundamentalism and orthodoxy acted. Christian theology tried to find a way between these two wrong behaviors, and in doing so they became the founders of a definitively Christian Theology.
Justin Martyr, perhaps the most important of the Apologists: “This is the only philosophy which I have found certain and adequate.” This sentence needs a comment. Some anti-apologetic theologians – they are not only in continental Europe – would say: Now there you see: Christianity is dissolved into a philosophy; that is what the Apologists did and that is what every apologetic theology does — even my own. I have heard this several, or even innumerable, times. The situation must be understood: what does this sentence mean, actually? Certainly it says Christianity is a philosophy. But if someone makes such a statement, one must know what philosophy means, in the mouth of this man, who was not a professor of philosophy, in America in the year 1953, in one of the colleges or universities. A Greek philosopher was something quite different. Philosophy at that time was the name for the spiritual, non-magical and non-superstitious character of a movement. Therefore! Justin says that Christianity is the only certain and adequate philosophy, he first of all says it is not magical, it is not superstitious; it is meaningful, adequate, to the logos, to the word, to reason; and this was the first thing he had to say against people like Celsus.
Secondly, for the later Greeks, philosophy was not only a theoretical but even more practical matter. It was a matter of existential interpretation of life, of an interpretation of life which was a matter of life and death for the existence of the people at that time.