The Gospel Coalition's claim that there is no Christ-honoring objective ground for knowledge between a believer and unbeliever is, first of all, inseparable from the epistemological question of whether TGC actually embraces a correspondence or coherence view of truth. Ordinarily, when one claims (as the council does) “we affirm that truth is correspondence to reality,” this means that propositions can be objectively and verifiably tested against reality and thus proven to be true or false. It also implies that truth is in some sense universal and accessible to everyone. From that standpoint, no matter what group, culture, or background one may belong to, the same reality is there and reliably knowable. Hence, with a correspondence approach, whenever the truth of a matter is under question, we may often gain the public clarity we need through facts or evidence. On the other hand, if only a specially qualified group of people can know truth (because they know things others don’t or, especially, because how they know things is different), then truth is not what corresponds to reality but what coheres with what those particular people believe—that is, their presuppositions as a group. Such an approach to truth reflects a coherence account of truth, which may be defined as, “truth is what coheres or is consistent with everything else we—not as the public or people in general but as a private or particular group—believe.”
But this presents a problem. Whatever its value in other contexts (such as religion), where public truth is concerned, such as in a court of law or everyday life, the coherence theory does not work. The reason is obvious: by definition such a theory does not claim the kind of neutrality, universality, or objectivity necessary for those contexts. Coherence truth is, in a certain sense, private truth or truth “for members only.” It assumes there are different rationalities or perspectives—no one rationality or perspective. Hence, it cannot—in its claim to knowledge and by definition—include everyone the way a correspondence account of truth does. What would happen, for instance, if a defense attorney employed an argument based on a way of knowing unique to himself or the defendant? How far would he get in a court of law? His conclusion might be reasonable or true for him and his client (his private club, in that sense), but it would not be reasonable or true for the rest of those involved in the trial: the attorney for the prosecution, the judge, the jury, and the public at large.
It may be helpful here to pause for a moment and recall that in the history of Western philosophy the coherence theory was formulated specifically due to a prior rejection of the correspondence theory. Indeed, the coherence theory serves for many (especially in philosophy) not only as a counter to the correspondence theory but also a worthy substitute for it. This does not mean, of course, that there is no coherence of beliefs within the framework of a correspondence theory. Nor does it mean, on the other hand (quite importantly in this context), that there is no claim of correspondence to reality within the framework of a coherence theory. (As I will explain shortly, this is where I believe TGC’s own claim to correspondence belongs.) It does mean, however, that with a coherence theory, at no point along the range of what it claims to know (even when it is most confident) does it propose for its knowledge the kind of correspondence to reality which, consistent with the theory so named (and, again, to which coherence is opposed), is objective, verifiable, and accessible to all.
This is why, of course, knowledge based on coherence is called “a web of belief.” Knowledge of this sort—in contrast to the groundedness of correspondence—is, as it were, suspended in mid-air. Such knowledge, though held together, has no connection to the earth in the sense that it has no foundation in what is (again) generally, reliably, and verifiably knowable for everyone. A coherence theory, therefore, is a special approach to truth, designed to accommodate what diverse groups, collectives, or cultures believe sans any direct, objective, and universal epistemic justification in external reality.
Hence, this theory of truth is consistent with knowledge regarded as subjective and relative. It is, in other words, pluralistic or perspectival in nature. This is because its basic assumption is that, for any particular group, its way of knowing (distinct from what it knows that way) uniquely, radically, and necessarily conditions what it counts as knowledge. Consequently, its knowledge is not shared by other groups. Put differently, a coherence theory holds that there is no one way of knowing available to everyone. In order, then, for Group A to convince Group B to adopt its beliefs, its appeal to truth can only be indirect. That is, Group A appeals directly neither to what it knows (based on its way of knowing) nor to something objective and knowable by all (since, of course, it doesn’t believe that things are known that way) but to its way of knowing (its presuppositions). With a coherence theory, then, if Group A wishes to persuade Group B to accept its truths, it does so by, in effect, making the following proposal: “Please try our way of knowing, and then, perhaps, you will accept what we know—that is, become convinced of and embrace our truths.”
With that said, I suggest that — notwithstanding its explicit identification with a correspondence theory of truth and rejection of “truth as nothing more than the internally coherent language of a particular faith-community” — TGC actually supports a coherence theory that includes an internal claim to correspondence. To make this case, I begin with Phillips:
The purpose of this booklet, then, is not to present an objective epistemology that anyone—Christian or not—would adopt....Wouldn’t it be better, some will ask, to meet our unbelieving neighbors on an objective epistemological common ground? That answer is that no such objective ground exists...
For the moment, I have intentionally omitted important qualifiers in this quotation, which I intend to include and address shortly. However, I wish to underscore in the quotation that in context the denial of an “objective epistemological common ground” is not what unbelievers are espousing under the sway of what Phillips elsewhere calls “today’s relativist hegemony.” Rather, this is Phillips himself (on behalf of The Gospel Coalition) speaking. That is, at this point, Phillips is not accommodating himself for the sake of the gospel to a subjective or relativistic age. This means (or so I argue) that what is both fundamental and critical to the correspondence theory of truth itself, namely, the implied assumption of a reality which can be known and verified by all, is not part of Phillips’ approach to truth. However, once this assumption is rejected, some other theory of truth than that of correspondence has to take its place. As I hope to show, next, that theory is one of coherence.
Now for the qualifiers I left out from the quotation: after rejecting “an objective epistemological ground” which is the same, whether one is a Christian or not, Phillips offers an alternative to that ground, which is an approach to truth based on the Christian faith itself. The latter, he says, “reflects the core beliefs of our gospel faith,” “validates our experience as Christian believers,” “presents how we as Christians answer questions regarding the knowledge of truth,” and honors “the lordship of Jesus.” Here the implication seems clear that if in presenting the gospel to unbelievers Christians assume that there is “an objective epistemological ground” between believer and unbeliever (that is, make a direct appeal to the truth), then they are, in that particular engagement, failing to honor (at least to some extent) their Christian faith and their Lord. And, as for the unbeliever with whom we are speaking about the gospel, there is apparently no basis for communication or persuasion apart from getting them to first presuppose Christian beliefs in general. (That is—and in a sense—they need to believe in order to believe.) Thus we have something quite similar to my earlier illustration of the coherence theory in action. Group A says to Group B, “Please try our way of knowing, and then, perhaps, you will accept what we know—that is, become convinced of and embrace our truths.”
As for how, specifically, TGC and Phillips internalize their own claim to correspondence within a coherence theory of truth, it seems to go something like this. Because of finitude and sin, humans cannot know truth. However, when someone is regenerated, they are able to understand the Word of God whose perfect knowledge alone corresponds to reality. The regenerate, therefore, have in this way unique access to objective truth; however, this comes not directly but indirectly. It is mediated through God and the Bible as the Spirit imparts understanding to the heart. Consequently, truth gets defined as what coheres to what God says in Scripture (again, which is known subjectively by the Spirit) and any claim of correspondence to external reality is located within that coherence. Conversely, those who are not regenerate (thus lacking the internal principle necessary for knowledge — and due to human finitude and sin) have no reliable, epistemic access to objective truth.
This means that there is a significant ambiguity in Phillips’ statement: “Prior to giving our witness to Christian truth, we will often have to present clear Christian views about truth itself.” If by a Christian view of truth, Phillips means a correspondence view of truth (a knowledge, in a sense, accessible to everyone the way other things ordinarily are) as supported by the Bible, that is one thing. (That, however, doesn’t seem to be what he is saying.) If, on the other hand, by a Christian view of truth (or “our witness”), he means (or implies) that truth is itself entirely relative to one’s subjective presuppositions, experience, or perspective, that is another. If he means the latter, he is saying something philosophical not biblical. He is also, quite significantly, conceding considerable ground to relativism itself—albeit, in the name of a Christian form of relativism. In that case, for instance, those postmodern unbelievers who say, “No thank you,” to our invitation as Christians to, “Please try our way of knowing,” will tend to walk away feeling — precisely because of this approach — justified and even confirmed in their own relativism.
Now my claim that Phillips is enlisting a coherence approach to truth is further confirmed by his account of a conversation between James Boice and a woman on an airplane. As an unbeliever, the woman had objections to the Christian faith. However, Boice kept asking her, “But is it [the Christian faith] true?” Phillips asks us to suppose that she was a relativist and did not believe in truth as a common ground. In context, he is imagining for us a problem we may face in talking to postmodernists about the gospel. And since we have already noted that Phillips himself does not believe in truth as a common ground, this is a bit puzzling, but let us continue. He then asks: “How, then, are Christians to proclaim truth in a world that no longer believes in it?” Phillips continues: “The answer to the challenge of our times is surely not to turn aside from our biblical witness to argue complicated theories of epistemology and hermeneutics.” Apart from what might be a questionable assumption that arguing “complicated theories of epistemology and hermeneutics” constitutes turning “aside from our biblical witness”—not to mention that he is from the outset already significantly vested in such “complicated theories”—Phillips’ encouragement is for us to simply give this person a Bible, tell how God has met our own subjective need for truth by sending his Spirit to provide what is written there, including what it tells us of God’s own Son, Jesus Christ, who gives understanding to sincere seekers of truth from God’s Word. However, again, is this not basically saying to that person, “Please try our way of knowing”? And, as I already indicated, is that not what relativists or those who support a coherence view of truth say in commending “their” truth to others?
Of course, it is a wonderful thing, when someone is willing to receive a Bible from us, especially when they are intent on weighing whether or not the gospel is true. However, as a general strategy for bringing the gospel to postmodern unbelievers, I wonder: Is that sufficient? Furthermore, if we do persuade such people to essentially “believe in order to believe,” what kind of converts will they be? Did they believe because the Bible and the Christian faith are true (Boice’s concern)? Or did they believe because they experienced it as true? Did they separate reason from faith in their conversion? Did they put their minds on hold, suspend their judgment, in order to believe?
In addition, Phillips says early in his book that “it will not suffice [emphasis mine—jnp] to hold forth our Bible and walk friends down the famous ‘Romans Road’ series of evangelistic verses.” He explains that due to the relativism of our times, we will also need to answer questions as to why we should accept the Bible as true or why we should think what is true for us is true for others, etc. Now I must confess that when I first read this reference to “the famous ‘Romans Road’ series of evangelistic verses” I wasn’t sure what this meant. I found on the internet that it involves a series of verses from Paul’s Epistle to the Romans to support the following truths:
1. Everyone needs salvation because we have all sinned (Rom. 3:10-12, 23).
2. The price (or consequence) of sin is death (Rom. 6:23).
3. Jesus Christ died for our sins. He paid the price for our death (Rom. 5:8).
4. We receive salvation and eternal life through faith in Jesus Christ (Rom. 10:9-10, 23).
5. Salvation through Jesus Christ brings us into a relationship of peace with God (Rom. 5:1; 8:1, 38-39).
As I read these bulleted points, it occurred to me that if one were to study all the gospel messages recorded in The Acts of the Apostles, these “Romans Road” points are all either explicitly or implicitly expressed there. The only difference is that in the apostolic presentation of the gospel, we find a consistent pattern of appeal (summarized in 1 Cor. 15:1-8) to the fulfillment of Scriptural prophecies as well as to their own eyewitness testimony as apostles to argumentatively support the conclusion that Jesus of Nazareth is Messiah and Lord. Hence, the “Romans Road” approach to evangelism is an elaboration of appropriate conclusions related to and even inseparable from this central conclusion of the apostolic proclamation of the gospel. As such (I trust this is fair), Phillips may as well have said, “When it comes to evangelizing those who are postmodern, it will not suffice to preach what the apostles preached in The Book of Acts or what Paul commends as the gospel with its evidence and proofs in 1 Corinthians 15. We should, instead, hand them a Bible and invite them to experience the truth subjectively for themselves.” This also means, when Phillips says (as noted above) that “in many cases” the “Romans Road” approach “will not suffice,” what in the end he really seems to mean is that it “will not do.”
Admittedly, at the risk of a simplistic reduction of Phillips’ argument, I wonder if, even in our postmodern times, there is no relevance or direction given us in Paul’s sacred charge to Timothy: “Preach the Word” (2 Tim. 4:2)? That is, does Paul say, “Hand out the Scriptures” (though, if possible, that would certainly be an important supplement to preaching the Word)? Such a charge would seem to recommend, again, a silent approach to evangelism (to use D.A. Carson’s phrase, a “gagging of God”). It seems to mean something like, “Don’t talk to people about Jesus, especially if they are relativists. Let them get the gospel on their own, subjectively, by reading the Scriptures and the help of the Holy Spirit.” However, what Paul says to Timothy with this charge to “preach the Word” (or what Peter says with his, “be prepared to make a defense to anyone who asks you for a reason for the hope that is in you”—1 Pe. 3:15) seems to be a direct counter to any prescription for a silent, subjective, or “try it you’ll like it” approach to evangelism. It is, notably (in Paul’s case), even more than directing Timothy to use words or speak to others directly about Jesus—even more than making a claim supported by reasons (though it surely includes as much)—it is, indeed, proclamation of an objective, public truth.
Hence, it seems to me that the explanation for why there is in Phillips a questioning (if not abandonment) of the “Romans Road” (or, as I propose, apostolic) approach to evangelism or of preaching and reasoning itself is that activities of this nature are logically consistent with the correspondence theory of public truth (which Phillips and TGC reject). However, a coherence theory (which apparently Phillips accepts), as a non-public, private, or exclusive account of truth, calls for a different approach altogether. The latter is obviously more subjective in nature and logically implies a manner of relating to people which is more indirect, less confrontive, and gently encourages people to get things on their own. Hence, instead of the urgent, direct, and passionate, apostolic call (such as one observes consistently in Acts) — expressed through preaching — to consider what the Scriptures say about Jesus as the Messiah as well as the apostles’ own testimony to the same (all accompanied with persuasive reasoning, etc.), under a coherence approach (as we see with Phillips' and TGC’s recommendation), it is the Christian perspective itself (not specifically the gospel) which is presented in a more indirect manner, that is, by handing someone a Bible and praying that through reading the Bible that person will have a believer’s subjective experience of the gospel as truth.
 In his Think: The Life of the Mind and the Love of God, TGC council member John Piper seems to recognize this universal aspect of truth in several places, for instance, when in contrast to this aspect he characterizes relativism as the belief that “there is no objective, external standard for measuring the truth or falsehood of a statement” (p. 97). Also, in a message entitled, “The Challenge of Relativism,” Piper says: “The claim that there is no one standard for truth and falsehood that is valid for everyone is rooted most deeply in the desire of the fallen human mind to be free from all authority and to enjoy the exaltation of self.” Additionally, in What Ever Happened to Truth?, TGC council member Al Mohler writes, “It [the truth of the gospel] is objectively, historically, and universally true” (p. 59). Now this may be a misunderstanding on my part, but I think this means that Mohler believes that in some sense even unbelievers can understand the gospel even if they reject or disobey what they know.
 The coherence theory is generally regarded, particularly in its influence on contemporary thought, as originating with epistemological idealists in the modern tradition like Immanuel Kant. In his phenomenal-noumenal distinction, for instance, Kant believes we can only know things as they appear to us (the phenomenal) and not how they are in themselves (the noumenal). That is, we have no direct access to external (non-mental) reality. This means that there is no objective truth which is accessible to us as knowledge. Reality is conditioned by the mind such that all we have are relative and subjective perspectives or interpretations and never direct knowledge of reality itself. Put another way, knowledge is mediated through the mind and there is no way to verify that knowledge, thus mediated, actually corresponds to (or accords with) external reality. Hence, the emphasis with respect to truth becomes a matter of how beliefs hold together or cohere (as an internal, mental reality) rather than how they are or are not true to external or objective reality.
 This quotation is from the statement on truth at TGC website.
 Can We Know the Truth?, p. 8.
 Can We Know the Truth?, p. 15.
 Can We Know the Truth?, p. 7.
 Can We Know the Truth?, pp. 22-23.
 Can We Know the Truth, p. 7.
 In the end, Phillips’ recommendation that we simply hand someone a Bible implies that in relating the gospel to a postmodern unbeliever we actually do not answer these questions about the Bible’s authority or the objectivity of truth.