We start with Scripture as our highest authority in ALL things not mere reason. That includes apologetics.
“If we truly want to help men’s consciences so that they are not gripped by perpetual doubt, we must derive the authority of Scripture from a higher source than human reasoning, evidence or conjecture. We must, that is, base it on the inner witness of the Holy Spirit.
Although Scripture’s own majesty is enough to command our reverence, it really begins to affect us only when it is sealed in our hearts by the Holy Spirit. Being illumined by his power, we no longer believe on the strength of our own or of others’ judgment that Scripture is from God. Above and beyond all human judgment we conclude without question that it is given to us from the mouth of God himself, through the ministry of men. It is as if, in Scripture, we beheld with our own eyes the very essence of God. We cease, therefore, to look for proofs and probabilities on which to base our judgment; instead, we subject our judgment and intellect to Scripture, as to a source so high as to rule out the need for judgment. Not because we are like some who thoughtlessly embrace unfamiliar things only to tire of them once they become better known; but because we are very sure that in Scripture we have the unassailable truth. Nor because we are like the ignorant who are in the habit of surrendering their minds to superstition; but because we feel that in Scripture the express power of deity is displayed, kindling in us the desire to give conscious and willing obedience more powerfully than if only human will or knowledge were involved.
This, then, is a conviction which does not require reasons. Nevertheless it is also a knowledge which is based upon a very sound reason, since our mind has a firmer and surer place to rest than in any set of reasons. It is, finally, a feeling which can only spring from heavenly revelations. Here I am talking of nothing else than what every believer experiences in himself, except that my words do not do justice to so worthy a theme, and are most inadequate as an explanation.
Unless we have a higher and firmer certainty than any human judgement can provide, there is no point proving the authority of Scripture by rational argument: it cannot be established on the basis of the church’s consent nor can it be confirmed by other evidences. For if this foundation is not first laid, it is bound to remain in abeyance. Once, however, we obediently accept Scripture as we should, and place it beyond all doubt, the reasons which before were not strong enough to impart certainty to our hearts will now appear as valuable aids.”
– John Calvin, The Institutes of the Christian Religion. p.20-21 (John White’s translation of 1541 version)
Urban Reformed Theology 