Christian theism's fundamental contention is just this, that nothing whatsoever can be known unless God can be and is known, and by God we mean the triune, self-sufficient God and his revelation of himself to man and his world - Cornelius Van Til
The term “epistemology” comes from the Greek words “episteme” and “logos”. “Episteme” can be translated as “knowledge” or “understanding” or “acquaintance”, while “logos” can be translated as “account” or “argument” or “reason”.
Stanford Encyclopedia of Philosophy
How do we know what we know? How do we obtain knowledge? These are the questions that are related to epistemology. We've already discussed A Christian Ontology and it would a helpful pre-reading before digging into this article. Remember that in a Christian ontology there are two levels of being: Creator and creation. We now need to apply this when talking about a Christian epistemology:
Just as there are two levels of being—God’s being as ultimate and absolute, and created being as derivative and dependent, so also there are two knowing subjects—God, whose knowledge is ultimate and absolute, and man, whose knowledge is derivative and dependent.
God’s knowledge is co–extensive with all that is. All created things fall within the compass of God’s knowledge because nothing in this universe is outside of the plan and will of God. It is God’s plan, and God’s will that executes the plan, that makes all things what they are. This means that God knew all created things in all possible and actual relationships even prior to their creation, and that it is because of His plan that all things became finally and actually what they are (cf. 1 Sam. 2:3; 16:7; 23:10–13; 1 Chron. 28:9; Ps. 139:1–4; 147:4; Isa. 19:15; 40:27–28; 42:9; Jer. 17:10; Acts 2:23; 4:24–28; Rom. 9:16; 11:33; Eph. 1:11; Phil. 2:13).
Reymond, The Justification of Knowledge, pg. 28
Keep the preceding in mind as we try to work through the concepts.
Before we continue, it's important that you know I'm not a philosopher, nor was I ever trained in theology, philosophy or apologetics. I simply have a passion for these areas of investigation and I like to try and stretch my mind to grasp the concepts and make them more accessible for the everyday reader.
The epistemology of Van Til that is described as a "revelational epistemology" is at the heart of presuppositional apologetics. Dr Richard Howe grasps this and regularly states that the point of differentiation between presuppositional and classical apologetics is the stance on epistemology. In Greg Bahnsen's debate with RC Sproul, everything that was said built op to the epistemological difference between the two debaters. Before we dig into the epistemology of Van Til, it will do us well to talk about some background.
Secular Epistemologies vs Christian Epistemology
A Christian brother of mine that I met through the Reformed Presuppositional Apologetics facebook group shared a paper of his with me titled "A Van Tillian Philosophy". He makes a remark in there that I think is important to raise near the start of our investigation:
Van Tillian epistemology of revelation is completely different from any secular or Thomist epistemological theory. Within any other epistemological theory, no distinction is made regarding: (1) the knowledge of God as a regenerate epistemic agent, (2) the knowledge of God as an unregenerate epistemic agent, (3 and 4) the knowledge of things or propositions as a regenerate or unregenerate epistemic agent. Other epistemological theories does not account for the spiritual state of the epistemic agent (specifically, the notion of total depravity ) and therefore would flatten all of these different types of knowledge into one type. This comes into major play when attempting to map contemporary epistemological theories onto these types of knowledge...
Van Til expressed the same thought in his "A Survey of Christian Epistemology" as he reaches the end of the book.:
The thing that has gradually shown itself to be of momentous importance is this fact that all reasoning in the field of knowledge must take into consideration the difference between those who accept and those who reject Christian theism. Whatever method we employ will have to figure from the outset with this difference.
Van Til, Survey of Christian Epistemology, pg. 173
Since no secular epistemology draws any distinction between the epistemological state of the regenerate and the unregenerate, we expect that a distinctly Christian epistemology will difficulty map to secular epistemologies, or at the very least will have some very unique features when compared to them.
Definition of Knowledge
I agree with the definition of knowledge as justified, true belief:
Whenever a knower (S) knows some fact (p), several conditions must obtain. A proposition that S doesn’t even believe cannot be, or express, a fact that S knows. Therefore, knowledge requires belief. False propositions cannot be, or express, facts, and so cannot be known. Therefore, knowledge requires truth. Finally, S’s being correct in believing that p might merely be a matter of luck. For example, if Peter believes he has a fatal illness, not because he was told so by his doctor, but solely because as a hypochondriac he can’t help believing it, and it turns out that in fact he has a fatal illness, Peter’s being right about this is merely accidental: a matter of luck (bad luck, in this case). Therefore, knowledge requires a third element, one that excludes the aforementioned luck, and so that involves S’s belief being, in some sense, justifiably or appropriately held. If we take these three conditions on knowledge to be not merely necessary but also sufficient, then: S knows that p if and only if p is true and S justifiably believes that p. According to this account, the three conditions—truth, belief, and justification—are individually necessary and jointly sufficient for knowledge of facts.
Stanford Encyclopedia of Philosophy
The definition of knowledge as justified true belief as received some criticism, however, most notably from Edmund Gettier in what has come to be known as the Gettier counter-examples . You can follow the reference to read up some more, or you can check out one of our forum posts on the topic.
Greg Bahnsen in his article titled 'The Heart of the Matter' wrote:
Knowledge includes having justification or good reason to support whatever it is you believe. Imagine that I believe there are thirty-seven square miles in a particular city, and imagine also that it just so happens that this claim is accurate - but imagine as well that I simply got this answer by guessing (rather than doing measurements, mathematics or checking an almanac, etc.). I believed something which happened to be true, but we would not say that I had "knowledge" in this case because I had no justification for what I believed. When we claim to know that something is true, we are thereby claiming to have adequate evidence, proof or good reason for it.
Bahnsen, The Heart of the Matter
Van Til further writes of knowledge:
For the Christian system, knowledge consists in understanding the relation of any fact to God as revealed in Scripture. I know a fact truly to the extent that I understand the exact relation such a fact sustains to the plan of God.
Van Til, Survey of Christian Epistemology, pg. 15
Bosserman re-enforces Van Til's point:
... knowledge is a matter of reflecting the mind of God, by allowing His special revelation to inform man’s interpretation of every other matter...
Bosserman, The Trinity and Vindication of Christian Paradox, pg. 108.
One self-admitted problem of Van Til is a lack of textual support for some hard hitting points that he makes throughout is writing. This does not mean that Van Til was unscriptural, but that Scripture was integrated into his writing in an implicit way . So, why did Van Til state the above? I'm going to quote three brief texts to substantiate Van Til's point before moving on.
The Bible also speaks clearly on knowledge:
The fear of the Lord is the beginning of knowledge; fools despise wisdom and instruction.
Proverbs 1:7, ESV
The meaning of Proverbs 1:7 is quite clear. Matthew Henry provides the following commentary: [Solomon] lays down this truth, that the fear of the Lord is the beginning of knowledge; it is the principal part of knowledge (so the margin); it is the head of knowledge; that is, of all things that are to be known this is most evident, that God is to be feared, to be reverenced, served, and worshipped; this is so the beginning of knowledge that those know nothing who do not know this.
For the Lord gives wisdom; from his mouth come knowledge and understanding;
Proverbs 2:6, ESV
As Christians, how can we expect to gain any knowledge or understanding separately from God?
[Christ] in whom are hidden all the treasures of wisdom and knowledge.
Colossians 2:8, ESV
Van Til went so far as to claim that even to believe that you can understand one fact ('know') without reference to God would make one 'anti-theistic'. Why? To believe that knowledge can be obtained without reference to God is to deny the clear teaching of Scripture that God is the one who provides us with knowledge, and that the fear of the Lord is the beginning of knowledge, and that in Christ we find ALL the treasures of wisdom and knowledge.
Bahnsen wrote that Paul infallibly declared in Colossians 2:3-8 that "All the treasures of wisdom and knowledge are hid in Christ." Note he says all wisdom and knowledge is deposited in the person of Christ - whether it be about the War of 1812, water's chemical composition, the literature of Shakespeare, or the laws of logic! Every academic pursuit and every thought must be related to Jesus Christ, for Jesus is the way, the truth, and the life (John 14:6). To avoid Christ in your thought at any point, then, is to be misled, untruthful, and spiritually dead. 
In summary, knowledge can briefly be defined as justified, true belief with the justification for the belief at a fundamental level being rooted in God's revelation. There will be no justification for belief in any fact (hence no knowledge) apart from God's revelation, but we'll get back to this.
Theories of Truth
Truth is one of the central subjects in philosophy. It is also one of the largest. Truth has been a topic of discussion in its own right for thousands of years. Moreover, a huge variety of issues in philosophy relate to truth, either by relying on theses about truth, or implying theses about truth. 
So, what is truth? The way you answer this question will depend on the theory of truth to which you subscribe. Popular theories include: The correspondence theory of truth: Truth is that which corresponds to reality, the coherence theory of truth: the truth is that which coheres with a beginning (certain) set of propositions and the pragmatic theory of truth: the truth is whatever works. The most common theory of truth espoused today (especially by classical Christian apologists is the correspondence theory of truth as defined by Aristotle). The dominant theory of truth in 20th century philosophy was that of the coherence theory of truth, and this is also the context in which Van Til found himself.
For the Christian, what would we define as truth?
Jesus said to him, “I am the way, and the truth, and the life. No one comes to the Father except through me."
John 14:6, ESV
Can we as Christians affirm the secular coherence theory of truth or the correspondence theory of truth? Van Til says no, but doesn't discard it completely:
[Correspondence] usually [in the secular philosophy] means a correspondence between the idea I have in my mind and the “object out there.”... We may call our position in epistemology a Correspondence Theory of Truth, if only we keep in mind that it is opposed to what has historically been known under that name... True human knowledge corresponds to the knowledge which God has of himself and his world.
Van Til, Survey of Christian Epistemology, pg. 11
It is our contention that only the Christian can obtain real coherence in his thinking. If all of our thoughts about the facts of the universe are correspondence with God’s ideas of these facts, there will naturally be coherence in our thinking because there is a complete coherence in God’s thinking... In a way it might be well for us to call our position the Coherence Theory of Truth because we claim to have true coherence. Whether we call our position a correspondence theory or whether we call it a coherence theory, we have in each case to distinguish it sharply from the theories that have historically gone by these names... For God, coherence is the term that comes first. There was coherence in God’s plan before there was any space-time fact to which his knowledge might correspond, or which might correspond to his knowledge. On the other hand, when we think of human knowledge, correspondence is of primary importance. If there is to be true coherence in our knowledge there must be correspondence between our ideas of facts and God’s ideas of these facts. Or rather we should say that our ideas must correspond to God’s ideas.
Van Til, Survey of Christian Epistemology, pg. 12
Christian View on Truth
For the Christian, the truth is that which corresponds to the mind of God. When our thinking corresponds to God's thinking, naturally our thoughts will logically cohere as well. Van Til writes that we might never have complete or exhaustive knowledge of a fact, but we can still have knowledge of something (e.g. a cow) insofar the knowledge that we do have is in correspondence with God's knowledge of the cow. Naturally we might ask, but how might we be sure that our knowledge corresponds to God's knowledge of the cow? We'll get to that soon, but in short, it comes down to our dependence on revelation.
The situation can be graphed as follows, borrowing from Bosserman's Trinity and the Vindication of Christian Paradox:
For the Christian, truth can be defined as that which corresponds to the mind of God, in which there is absolute coherence. We close this section with another quote by Bosserman:
A true belief corresponds to the mind of God because it is formed in faithful submission to the Word of Christ, while a false belief does not correspond to the mind of God, because it refuses the illumination of Christ. A true belief is coherent because it is informed by that Being Who holds all things together, and a false belief is incoherent because it is ultimately informed by an empty void. Hence, alluding to 1 Corinthians 10:5, Van Til offers the rather straightforward definition of “analogical”* reasoning: “To make every thought captive to the obedience of Christ speaking in Scripture, is to reason analogically in the proper sense of the term.
Bosserman, The Trinity and Vindication of Christian Paradox, pg. 114.
* Van Til distinguished between two ways of reasoning. The first is univocal reasoning and the second analogical reasoning. Analogical reasoning considers man as the derivative and God as ultimate, whereas univocal reasoning will treat man as ultimate and God as derivative. Hence, for any to know any truth at all, they need to reason analogically.
Epistemic Theories of Justification
Now that we've discussed knowledge as a true belief that requires justification, and defined truth as that which corresponds to the mind of God, we can turn to the issue of justification. Epistemic theories of justification involve the chosen method of justification for our beliefs. Say that I believe X, for X to be knowledge it first needs to correspond to the mind of God, and I need a sufficient justification for believing that X is true (corresponds to the mind of God). Epistemologists have disagreed on what sort of conditions must be fulfilled in order to raise a true belief to the status of knowledge (i.e. justified), and where these conditions must be found.
It would be improper to claim to know something if we don't have a justification for the belief we claim to know. We can't claim to know something if we've just come to believe it by chance or luck.
At the start of this section I'm going to break all the rules of writing and quote from Wikipedia. They provide a good list of available theories of justification (although take their explanations with a grain of salt, my only point is to show that over the years people have been grappling with this problem and have proposed different solutions):
Foundationalism – Basic beliefs justify other, non-basic beliefs.
Epistemic coherentism – Beliefs are justified if they cohere with other beliefs a person holds, each belief is justified if it coheres with the overall system of beliefs.
Infinitism – Beliefs are justified by infinite chains of reasons.
Foundherentism – A combination of foundationalism and epistemic coherentism
Internalism – The believer must be able to justify a belief through internal knowledge.
Externalism – Outside sources of knowledge can be used to justify a belief.
Reformed epistemology – Beliefs are warranted by proper cognitive function, proposed by Alvin Plantinga.
Epistemic skepticism – A variety of viewpoints questioning the possibility of knowledge
Evidentialism – Beliefs depend solely on the evidence for them.
Reliabilism - A belief is justified if it is the result of a reliable process.
Now admittedly this is where the waters get muddy and I don't think I'm nearly qualified enough to give a "correct" (or even reasonable) answer here. Presuppositionalist scholars disagree what to make of Van Til when it comes to justification. I'll do my best to walk through the answer I've found most convincing from Brant Bosserman.
Bosserman writes the following on Van Til's position regarding the above:
[The] problem of epistemic justification does not arise for Van Til in the same way that it does for contemporary philosophers...
Bosserman, The Trinity and Vindication of Christian Paradox, pg. 119.
To better understand how we might approach the issue of epistemic justification from a Christian perspective, we first need to ask whether a non-Christian can have true beliefs. Recall that the problem of epistemic justification is traditionally defined as the method of justifying already held true belief. Is the issue for the unbeliever only a matter of seeking a justification for their currently held (individual) true beliefs?
The (professed) beliefs of unbelievers by their very nature will be anti-Christian and false (as the unbeliever does not perceive any truth as a created truth, although by God's common grace unbelievers are restrained from thinking and acting in perfect accordance with their false beliefs, and thus, from succumbing to the pure confusion and self-destruction of sin (Prov 8:36; Jer 2:13, 19; Matt 16:25).) 
For the unbeliever, it's therefore not a matter of seeking justification for already held true beliefs, it's about a complete shift in thinking to bring man's thoughts in line with God's thoughts:
For Van Til, affirmation of simple mathematical equations (e.g., 3 + 1 = 4), and basic matters of fact (Mount Everest is over 29,000 feet high), are basically false (and frustrating to human enterprise) when the matters involved are not conceived of as creations, which exists as they do, by and for the plan of God.
Bosserman, The Trinity and Vindication of Christian Paradox, pg. 116.
This is where the distinction between univocal and analogical reasoning comes in. Unbelievers proceed to reason in a univocal manner, making themselves ultimate and hence refusing to see facts as created facts finding their ultimate origin in the mind of God. Every belief belongs to a holistic “belief system” that encompasses definite ideas about man, creation, and God. Hence, no belief stands on its own ground. The Bible supports the following view:
In Romans 1 Paul teaches us that God is revealed to us through that which is made such that all men are without excuse. Therefore, to know any fact would be to know God. And to claim to know any fact whilst also claiming not to know God would logically mean that the fact is not known, or falsely known. As another example, according to Scripture, the moment that someone forms a belief about the sky, he simultaneously affirms certain beliefs about himself, his relationship to the sky and his ability to be taught about God by the sky. See Psalm. 19:1.
But now, what are we to think of an unbeliever's belief when they say that they see a tree (when in fact they do), yet also exclude the knowledge of God from their set of beliefs? Van Til would say that the unbeliever is involved in some form of rational / irrational dialect: Firstly, the unbeliever sees a tree, but since they regard either the one as ultimate or the many as ultimate (see the problem of the one and the many), they cannot give an account for the fact of a tree. Secondly, on any but the Christian basis, man, using his reason, is a product of Chance and the facts which he supposedly orders by the “law of contradiction” are also products of Chance. Why should a “law of contradiction” resting on Chance be better than a revolving door moving nothing out of nowhere into no place? Stated simply, for the unbeliever to say that they see a tree, they take the law on non-contradiction for granted in that implicitly they believe they are not seeing a "not-tree". 
The belief therefore has a rational aspect to it since it does correspond to something in reality, but is swallowed up in irrationality since it excludes the most fundamental part revealed in it: That is is created and sustained by God. Unbelievers are therefore able to form beliefs that on the surface seem rational and in line with ours, but it is their subsequent denial of what it reveals to them about God and themselves that makes their belief irrational and false.
As fallen creatures we aren't seeking for justification of already held true beliefs (as we don't have any), we're seeking justified true beliefs (knowledge) to overthrow our false beliefs, and this knowledge is of course only to be found in Christ. Oliphint notes that the rational / irrational dialectic cannot be resolved WITHOUT a conversion to Christ, which he got from Paul in Colossians 3:10. 
What I like about the Bosserman book at this point is how he outlines the centrality of the atoning work of Jesus in allowing fallen creatures to obtain justified true beliefs. Bahnsen mentioned this in his article on the Impropriety of Evidentially Arguing for the Resurrection:
It is correct to hold that God's raising of Jesus from the dead saves us both from sin and agnosticism, but it would be mistaken to understand by this that the epistemological problem could be handled independently of the (broader) moral problem which is at its base. It is with regret that one notices neo-evangelicals severing the justifying efficacy of Christ's resurrection from its truth-accrediting function. In reality, the latter is dependent upon the former. Only as Christ's resurrection (with its ensuing regeneration by the Holy Spirit of Christ) saves a sinner from his rebellion against God and God's Word can it properly function to exhibit evidence for God's truthfulness.
So according to Bahnsen, the resurrection of Jesus (and regeneration of the Holy Spirit) saves us sinners from our rebellion against God and His Word and allows us to view facts in light of God's truthfulness.
Because man has so mangled the image of God within Himself, and come under the wrath of his Creator, it is impossible for him to redirect his intellect toward the Truth, and justify his own beliefs. Instead, God the Son must assume human flesh and pacify the wrath toward humanity as a substitutionary sacrifice, and cleanse man’s conscience by setting him on a new course to serve God (Heb 9:14; Rom 5:1–2).
Bosserman, The Trinity and Vindication of Christian Paradox, pg. 121.
This is where things get important: the knowledge of Christ's sacrifice can only come through the Word itself (Rom 10:17), and can only be accepted through the work of the Holy Spirit. Without the Word, man will continue on his path of destruction and falsehood. When fallen man is confronted with the Word of Christ, and is regenerated by the Holy Spirit, he comes to fully realize the falsity of his beliefs beforehand and his mind is renewed (as new creatures in Christ). The Word then allows us to bring our thoughts into coherence those of God revealed in Scripture, which is ultimately true because of the Word's correspondence with the mind of God.
John 15:15 puts it quite well:
No longer do I call you servants, for the servant does not know what his master is doing; but I have called you friends, for all that I have heard from my Father I have made known to you.
John 15:15, ESV
We cannot obtain correspondence with the mind of God outside Christ and His Word. Only through Christ do we have the revelation of God that will allow us to gain true correspondence.
After the Fall, the only way that man can actively develop “true” conceptions of God, Himself, and reality is if the Holy Spirit should change his disposition toward the revelation of Christ and allow his beliefs to be overturned and refined by divine revelation. At the moment of conversion, one’s beliefs not only become true (as correspondent with the mind of God, and coherent with special revelation), they become justified (set on a trajectory to develop and to embrace ever greater depths of divine truth).
Bosserman, The Trinity and Vindication of Christian Paradox, pg. 125.
Our belief system is then justified when it has been set on a course by Christ and the Spirit to grow into an ever more robust belief system with a deeper, more profound, and more inspiring understanding of God, oneself, and creation. The characteristic belonging to a true belief system which renders it “justified” is the promised curatorship of Christ, who is “the Way, the Truth, and the Life” (John 14:6), and whose “Spirit of Truth” will certainly “guide you into all the truth” (John 16:13). 
As regenerated Christians, we no longer reason in a way that makes man ultimate, but rather God is ultimate and all we have and are is derived from God. When we approach His Word in this humble fashion and reason in this manner, we can hold fast that the Spirit will guide us into all the truth, and therein lies the justification of our Christian beliefs.
You'll remember this image from our article on Christian Ontology:
We've already touched on the subject of revelation earlier in the article when we stated that "There will be no justification for belief in any fact (hence no knowledge) apart from God's revelation".
Van Til described revelation as follows:
According to Scripture, God has created the “universe.” God has created time and space. God has created all the “facts” of science. God has created the human mind. In this human mind God has laid the laws of thought according to which it is to operate. In the facts of science God has laid the laws of being according to which they function. In other words, the impress of God’s plan is upon his whole creation. We may characterize this whole situation by saying that the creation of God is a revelation of God. God revealed himself in nature and God also revealed himself in the mind of man. Thus it is impossible for the mind of man to function except in an atmosphere of revelation. And every thought of man when it functioned normally in this atmosphere of revelation would express the truth as laid in the creation by God. We may therefore call a Christian epistemology a revelational epistemology.
Van Til, Survey of Christian Epistemology pg. 11
Christianity is not merely the most tenable hypothesis that one can find for the interpretation of the world. Christianity is no hypothesis at all. It is accepted on the authority of the self-attesting Christ of Scripture and at the same time it is the presupposition without which predication is unintelligible.
Van Til, Survey of Christian Epistemology pg. 104
We have discussed that the unregenerate man cannot hold any true beliefs since they suppress the fundamental truth revealed in the facts around them, namely the existence of God. We have also discussed that the unregenerate man is made new by the Holy Spirit on hearing the good news of the Gospel which saves us sinners from our rebellion against God and His Word and allows us to view facts in light of God's truthfulness. As regenerate creatures, the Scriptures shine a new light on creation such that we can see it clearly as God has intended it:
... the object of knowledge is brought into right relationship with God once more. And an aspect of this restoration is that true light is thrown upon it by the Scriptures. The Niagara Falls cannot be seen at night unless there is a powerful searchlight that throws light upon them. The point of importance to note about this matter of Scripture is that according to the Christian theistic position the Bible is an inherent part of the system of theism as a whole.
Van Til, Survey of Christian Epistemology pg. 108
But the question that must still be answered is this: The first fact we came into touch with was not the fact of the Bible. Each and every person began their factual investigations without reference to the Bible. Are we arguing that we must go to the Bible to get all our facts? Let's say we want to go study some animal in the Kruger National Park in South Africa, would it not be absurd to rather consult our Bibles about that fact rather than actually going to see and study the animal?
Van Til answers, yes it would be absurd, but then elaborates that when we say that no fact can be understood apart from special revelation, we are not saying that Scripture contains ALL facts as indeed it does not. We are not speaking of getting definite bits of information about certain definite “facts” of biology or physics. However, whatever “fact” there may be in the Kruger National Park or anywhere else is a part of some great realm of “facts”. The very purpose of scientific knowledge is to set facts into relation to one another.
For example, when studying the animal in nature, we might encounter a dead animal. Without Scripture we might conclude that death is quite normal in nature. The Bible however offers a different interpretation of death - it is not natural and a serious problem. As another example, studying nature alone man might come to the conclusion that dead men cannot rise from the dead. The Bible however offers a different interpretation.
The Bible claims to have the ultimate truth on all facts. Ultimate in the sense that it provides the framework for proper interpretation of all other facts. To proceed on a factual investigation without the Bible is to already reject to the Bible's claim to authority on all facts.
Without the Scripture as the word of the self-attesting Christ we would know no fact for what it is, i.e., as set in the only framework in which it can have meaning.
Van Til, Survey of Christian Epistemology pg. 109
It is in special revelation where we are provided with the proper framework in which the understanding of all facts in the realm of facts (creation) can take place. There never was a time when God did not speak, and today we have His Word in written format.
We've already chosen to restrict our discussion to the question of epistemology in a post-fall world, but it is helpful to use as an example to situation of Eve in the garden. Eve had special revelation from God clearly stating that she is not to eat from the tree of knowledge of good and evil. Being deceived by Satan, she started to reason in a univocal manner hence regarding herself as ultimate. What God clearly told her would cause death, started to seem "nice to look at" and "good to eat from". She reasoned to completely wrong conclusions specifically because she chose to ignore special revelation as the interpretative lense for natural revelation (Genesis 3).
Moreover, without Special revelation which provides us with the Gospel of Jesus Christ, there would be no regeneration of sinners as repentance can only come upon hearing the Gospel, and if there is no regeneration, there is no proper understanding of the truth of facts and hence no knowledge.
We now turn to look at the concept of general revelation. In the beginning of this section on revelation we quoted Van Til as stating that, "God has created all the “facts” of science. God has created the human mind. In this human mind God has laid the laws of thought according to which it is to operate. In the facts of science God has laid the laws of being according to which they function. In other words, the impress of God’s plan is upon his whole creation. We may characterize this whole situation by saying that the creation of God is a revelation of God. God revealed himself in nature and God also revealed himself in the mind of man. Thus it is impossible for the mind of man to function except in an atmosphere of revelation."
Van Til is echoing what the apostle Paul taught us in the opening chapter of the letter to the Romans. Man knows God through revelation that is both inward and outward in relation to man. The sole purpose of general revelation is to leave men "without excuse". No one can come to redemptive knowledge of God from nature alone. We've published an article on this recently responding to critics who claimed that Van Til "sacrificed general revelation". This can be read here.
Men ought to realize that nature could not exist as something independent. They ought to sense that if anything intelligible is to be said about nature, it must be in relation to the absolute system of truth, which is God. Hence, they ought at once to see nature as the creation of God.
Van Til, An Introduction to Systematic Theology, pg. 180
The unregenerate man refuses to think in an analogical fashion. Regarding themselves as ultimate they are unable to correctly interpret general revelation (consider how Paul teaches in Romans 3 that all men have gone astray, no one understands, no one seeks God, all men's lips deceive). However, despite this, God has implanted in man an inescapable "sense of deity" as Calvin put it, and nature reveals his "eternal power and divine nature". The natural man knows this deep down and is dependent on their knowledge of God to make intelligible sense of creation, but rather suppresses this truth in unrighteousness.
Natural man is still created in the image of God and cannot help think and act in a certain way. Since God is rational and orderly, it is natural for man to act in the same way. They argue logically, they categorise the many into universals, they assume the uniformity if nature etc. and may reach a certain point of understanding of nature, but that understanding is ultimately swallowed up in irrationality since they also deny the God in which human predication is possible.
Moreover, all men everywhere, deep down in their hearts know that the world is created by God. At bottom they know that by all their attempts at explanation of nature they are suppressing within themselves the testimony of the real Creator of the universe...
Van Til, An Introduction to Systematic Theology, pg. 182
There has been countless attempts by men to remove the knowledge of God in their hearts in their attempts to explain the world around them, but even in these vain attempts God is revealed to them when they use rational means of argumentation, or even when they conclude irrationality in a last ditch attempt to avoid Him. But even there when man has concluded irrationality, it presupposes rationality and again God cannot be avoided.
To summarise before we move on, there is no fact that can be properly interpreted apart from God's special revelation. Both with respect to nature and with respect to man himself, men should have known God as Creator, as preserver and as Judge (see Romans 2)... they should have known Him as the one through whom alone all human predication, applied either to nature or to man has meaning. Instead of knowing him as such, men sought to interpret the universe by an exclusively immanentistic principle, as Paul says: "For they exchange the truth of God for a lie, and worshipped and served the creature rather than the Creator, who is blessed forever, Amen" (Rom. 1:25)... 
Through special revelation, we can be made regenerate upon hearing the Gospel of Jesus Christ through the Holy Spirit, in which we find a context of interpretation of facts that will render them both true and justified.
Since antitheistic thinking takes this univocal method of reasoning to be so evidently the only possible method of reasoning, since univocal reasoning is the reasoning of “the natural man,” which he will not and cannot forsake till he is no longer a “natural man” but a regenerated man, the one thing of importance to remember is that we must set over against this natural man not something that is a little modification of that which he already holds. We must hold before him the necessity of a total reversal of his attitude of mind.
It is this that Paul did when he preached the gospel to the wise men of Athens, steeped as they were in Plato and Aristotle. The Christian epistemologists have been all too remiss in fearing to follow Paul’s example boldly. They have feared that they would have no results if they were thus fearless in their approach. Yet if anything would seem to follow from the Christian position as a whole, it is that we could expect no results at all unless bold measures be taken.
If the whole head is sick and the whole heart faint, it is not a snuffbox that is needed, but a lively stimulant. If men are dead in their sins and trespasses they are dead epistemologically too, and no demonstration of health will do any good, but only the gift of new life. Accordingly, we must reason in such a way that the Holy Spirit can give life through our reasoning as an avenue.
Van Til, Survey of Christian Epistemology, pg. 175
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Van Til: The Theologian. 2020. Van Til: The Theologian. [ONLINE] Available at: https://frame-poythress.org/van-til-the-theologian/. [Accessed 26 July 2020].
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Bosserman, B A. The Trinity and the Vindication of Christian Paradox : An Interpretation and Refinement of the Theological Apologetic of Cornelius Van Til. Cambridge, U.K., James Clarke & Co, 2015.
Cornelius Van Til, Christian Philosophy
This point was further elaborated for my by Bosserman on my request.
K Scott Oliphint and Tipton, L.G. (2007). Revelation and reason : new essays in Reformed apologetics. Phillipsburg, N.J.: P & R Pub.
Van Til, C. and Edgar, W., 2007. An Introduction To Systematic Theology. Phillipsburg, N.J.: P & R Pub., p.182.