Descartes’ Philosophical Revolution
In the history of Christian philosophy, Anselm stands as one of the key figures. His idea that one must trust God (i.e. believe) in order to understood, was a high point in the Middle Ages.
But in the 16th century, Rene Descartes turned the world upside down. In trying to establish what he thought would be an indubitable starting point for human thought, his answer was the opposite to that of St. Anselm.
Cogito ergo sum—I think, therefore I am—placed the human mind as the unquestionable starting point in all human predication. Now, God and everything else would have to be proven by the mind of man that was now unlinked from everything. The mind of man was now autonomous.
Now the problem with this statement seems hidden from Descartes. And the problem is this. His idea of cogito ergo sum is not logical. It assumes what it is supposed to prove. Consider this syllogism:
P1. I think
P2. In order to think I must exist
C. Therefore I exist.
The problem is that the conclusion ‘I exist’ is assumed in the first premise: ‘I think.’ The moment the ‘I’ word is used, it assumes existence. In order to not beg the question, therefore, the first premise ought to be: ‘There is thinking going on,’ and you cannot get from there to ‘I exist.’ So, you can’t know that ‘you think’ because you have not justified that you exist. Consider the revised syllogism:
Van Til On The Law of Non-Contradiction (Contradiction) in Apologetics
Cornelius Van Til had this to say about the law of contradiction (or non-contradiction) in reasoning with the unbeliever. (A Survey of Christian Epistemology. The Presbyterian and Reformed Publishing Company: Phillipsburg, NJ., 1969, Chapter 15.)
We must therefore give our opponents better treatment than they give us. We must point out to them that univocal reasoning itself leads to self-contradiction, not only from a theistic point of view, but from a non-theistic point of view as well. It is this that we ought to mean when we say that we must meet our enemy on their own ground. It is this that we ought to mean when we say that we reason from the impossibility of the contrary. The contrary is impossible only if it is self-contradictory when operating on the basis of its own assumptions. It is this too that we should mean when we say that we are arguing ad hominem. We do not really argue ad hominem unless we show that someone’s position involves self-contradiction, and there is no self-contradiction unless one’s reasoning is shown to be directly contradictory of or to lead to conclusions which are contradictory of one’s own assumptions. . . .
We do not give in to defeat or appeal to irrationality in the name of faith, but we challenge their interpretation of the law of contradiction.
When we reason thus [i.e., placing ourselves in our opponents position – IH] we are not reasoning on the basis of some abstract law of self-contradiction. We have seen that the very question between theists and antitheists is as to the foundation of the law of contradiction. When they criticize our position and think they have reduced it to the place where it falls under the law of self-contradiction, we do not give in to defeat or appeal to irrationality in the name of faith, but we challenge their interpretation of the law of contradiction. We hold that they have falsely assumed that the self-contradictory is to be identified with that which is beyond the comprehension of man. But this takes for granted that human categories are ultimate categories—which is just the thing in question. We must maintain that we have the true conception of the law of contradiction. According to that conception, only that is self-contradictory which is contradictory to the conception of the absolute self-consciousness of God. If there were in the Trinity such a self-contradiction, there would also be in the matter of God’s relation to the world. But, since the Trinity is the conception by which ultimate unity and diversity is brought into equal ultimacy, it is this conception of the Trinity which makes self-contradiction impossible for God and therefore also impossible for man. Complete self-contradiction is possible only in hell, and hell is itself a self-contradiction because it feeds eternally on the negation of an absolute affirmation. Accordingly, we must hold that the position of our opponent has in reality been reduced to self-contradiction when it is shown to be hopelessly opposed to the Christian theistic concept of God. Yet in order to bring this argument as closely to the non-regenerate consciousness as we may, we must seek to show that the non-theist is self-contradictory upon his own assumptions, as well as upon the assumption of the truth of theism, and that he cannot even be self-contradictory upon a non-theistic basis, since if he saw himself to be self-contradictory he would be self-contradictory no longer.
Complete self-contradiction is possible only in hell, and hell is itself a self-contradiction because it feeds eternally on the negation of an absolute affirmation.
Now when this method of reasoning from the impossibility of the contrary is carried out, there is really nothing more to do. We realize this if we call to mind again that if once it is seen that the conception of God is necessary for the intelligible interpretation of any fact, it will be seen that this is necessary for all facts and for all laws of thought. If one really saw that it is necessary to have God in order to understand the grass that grows outside his window, he would certainly come to a saving knowledge of Christ, and to the knowledge of the absolute authority of the Bible. It is true, we grant that it is not usually in this way that men become true Christian theists, but we put it in this way in order to bring out clearly that the investigation of any fact whatsoever will involve a discussion of the meaning of Christianity as well as of theism, and a sound position taken on the one involves a sound position on the other. It is well to emphasize this fact because there are Fundamentalists who tend to throw overboard all epistemological and metaphysical investigation and say that they will limit their activities to preaching Christ. But we see that they are not really preaching Christ unless they are preaching him for what he wants to be, namely, the Christ of cosmic significance. Nor can they even long retain the soteriological significance of Christ if they forsake his cosmological significance. If one allows that certain facts may be truly known apart from God in Christ, there is no telling where the limit will be. It soon appears that the elephant wants to warm more than his nose. He will soon claim that the truths of the religious consciousness may also be known apart from Christ, and may therefore become the standard of what is to be accepted of the Bible.
The distinguishing characteristic between every non-Christian theory of knowledge on the one hand, and the Christian concept of knowledge on the other hand, is, therefore, that in all non-Christian theories men reason univocally, while in Christianity men reason analogically. By this distinction we mean that every non-Christian theory of method takes for granted, that time and eternity are aspects of one another, and that God and man must be thought of as being on the same plane. God and man must be thought of as correlative to one another. God and man work under a system of logic that is higher than both, and that exists in independence of both. The law of contradiction is thought of as existing somehow in independence of God and man or at least as operating in both God and man on the same level.
In contrast to this, Christianity holds that God existed alone before any time existence was brought forth. He existed as the self-conscious and self-consistent being. The law of contradiction, therefore, as we know it, is but the expression on a created level of the internal coherence of God’s nature. Christians should therefore never appeal to the law of contradiction as something that, as such, determines what can or cannot be true. Parmenides serves as a warning of what happens to history if the law of contradiction is in this fashion made the ultimate standard of appeal in human thought. Parmenides concluded that to understand anything historical, it would have to be reduced to an element in a timeless system of categories. He therefore denied the reality and significance of all historical plurality. In modern times it is customary to use the law of contradiction negatively rather than positively as Parmenides did. On the surface this appears to leave room for historical factuality. But it does so only if this historical factuality be thought of as being unknowable or irrational.
Christians should employ the law of contradiction, whether positively or negatively, as a means by which to systematize the facts of revelation. Whether these facts are found in the universe at large or in the Scripture. The law of contradiction cannot be thought of as operating anywhere except against the background of the nature of God. Since, therefore, God created this world, it would be impossible that this created world should ever furnish an element of reality on a par with him. The concept of creation as entertained by Christians makes the idealist notion of logic once for all impossible. The creation doctrine is implied in the God-concept of Christianity; deny the creation doctrine and you have denied the Christian concept of God. A created being or a created reality in general cannot furnish a novelty element that is to stand on a par with the element of permanency furnished by the Creator. If one believes in the creation doctrine at all, one has to say that the novelty element of the universe is subordinate to the eternal plan of God. Christians believe in two levels of existence, the level of God’s existence as self-contained and the level of man’s existence as derived from the level of God’s existence. For this reason, Christians must also believe in two levels of knowledge, the level of God’s knowledge which is absolutely comprehensive and self-contained, and the level of man’s knowledge which is not comprehensive but is derivative and re-interpretative. Hence we say that as Christians we believe that man’s knowledge is analogical of God’s knowledge.
Van Til, C. (1979). An Introduction to Systematic Theology. The Presbyterian and Reformed Publishing Company: Phillipsburg, NJ.
“Show me God!”
When the Street-Preacher steps up onto his podium, he can be sure to be confronted by competing claims about knowledge. “The Bible is true,” he will proclaim, “for God says so.”
And back will come the atheistic question: “But have you seen God?” Or it may be a demand, not a question: “Show me God.” This is the request “Matt the Horrible Atheist” (as in Hagar the Horrible) kept asking me on his last visit, too. He thought it was a winning question.
Embedded into the atheist’s question, though, is a belief about knowledge, a particular kind of knowledge. He wants to know if the Street-Preacher has ‘seen’ God. He asks this question because he believes that the only valid knowledge is empirical knowledge — knowledge via the senses.
Now seeing, along with taste, touch, smelling and hearing, is one of the five senses. And knowledge that is obtained via the senses is referred to as empirical knowledge. It is usually taken for granted that there is some correspondence between our senses and external objects. That is, we think we see a tree in the distance, and we expect that that tree actually exists in time and space. But ever since David Hume picked up his pen and wrote on the topic, knowledge by way of the senses has come under question. Instead of certainty of knowledge, Hume introduced skepticism. Is it really possible to have knowledge by sense perception?
At this point we must pause to clarify the logic both of this particular situation and of experimental verification in general. A simple argument of verification proceeds as follows: the given hypothesis implies certain definite results; the experiment actually gives these results; therefore the hypothesis is verified and can be called a law. Obviously, this argument is the fallacy of asserting the consequent; and since all verification must commit this fallacy, it follows that no law or hypothesis can ever be logically demonstrated.
It seems, however, that hypotheses can be logically proven false. The argument would go: the given hypothesis implies certain definite results; the experiment actually gives a contradictory result; therefore the hypothesis is false. Obviously, this is the perfectly valid argument of denying the consequent. So it would seem that although laws can be proven false, they can never be proven true.
- Gordon H. Clark, The Philosophy of Science and Belief in God (Nutley, NJ: Craig Press,  1977), p. 73.↵back
Professor John Lennox was recently in Australia — again. He’s a popular visitor to the land ‘down under’ because of his debates with atheist Richard Dawkins. It’s an interesting clash of professorial titans, since both of them held or still hold professorships at Oxford University. But while he was in Australia, Prof. Lennox was interviewed on the question of the age of the earth and the days of Genesis by Simon Short, a Director of the Centre for Public Christianity. That interview can be seen here: The 7 Days That Divide the World.
What is remarkable in this interview, however, is John Lennox’s defense of his view of Genesis chapter one as being longer than 6-days, i.e., six twenty-four periods of time. It’s remarkable because of what Prof. Lennox did say, and sometimes what he did not say. For example, he attempted to justify a metaphorical reading of the ‘days’ of Genesis because the Bible uses metaphor, and the example he uses is the reference to Jesus as a door. This is no doubt a metaphorical expression. But Prof. Lennox is surely begging the question to then suggest that the ‘days’ of Genesis are also metaphorical. This is what he is supposed to prove in his argument. But all he’s done is assume metaphor in one place allows him to read metaphor in another place. But what rule of biblical hermeneutics requires that? What has happened to the notion of context? If you follow Prof. Lennox’s ‘logic’, then it is possible to read metaphorically any time you don’t particularly like the non-metaphorical implications of a particular passage.
One must do a great deal of hermeneutical gymnastics to escape the plain meaning of Genesis 1-2.” —R.C. Sproul
And then, of course, there are the uses of the word ‘day’ in Genesis, which Prof. Lennox highlights. It means one thing here, perhaps 12 hours, another thing there, say 24 hours. And so it does. And in each case he uses context as the mechanism to understand how the word ‘day’ ought to be understood. But nowhere does he show contextually that the ‘days’ of Genesis are long periods of indeterminate time. He refers to ‘Hebrew scholars’ who apparently affirm that the ‘days’ of Genesis are not literal 24-hour periods. The trouble with this argument, however, is that there are Hebrew scholars who say otherwise. James Barr, wrote to David C.C. Watson in 1984,
‘… probably, so far as I know, there is no professor of Hebrew or Old Testament at any world-class university who does not believe that the writer(s) of Genesis 1–11 intended to convey to their readers the ideas that:
a. creation took place in a series of six days which were the same as the days of 24 hours we now experience
b. the figures contained in the Genesis genealogies provided by simple addition a chronology from the beginning of the world up to later stages in the biblical story
c. Noah’s flood was understood to be world-wide and extinguish all human and animal life except for those in the ark.’
Barr was a neo-orthodox scholar who did not necessarily accept what the Scriptures taught, but he seems certain that what they taught was a literal 6-day creation. So already we have a problem. I wonder which Hebrew scholars Prof. Lennox can be referring to? Dr. R.C. Sproul, in his commentary on the Westminster of Faith, admits that he used to hold to the frame-work hypothesis, but no longer holds that view.
“This phrase, ‘God can do all things,’ is rightly understand to mean that God can do all things that are possible; and for this reason He is said to be omnipotent.” ‐Thomas Aquinas
In the attempt to discredit God and Christianity all kinds of unusual questions are posed to the believer.
‘Can God make a square circle?’
‘Can God make a triangle with four sides?’
And the favorite, ‘Can God make a rock so big that he cannot lift it?’
And the conclusion? If God cannot do these things, then he is not all-powerful.
And so the skeptic thinks he has raised questions that disprove the Bible and Christian theology.
Christians who have a weak understanding often fall prey to these kinds of questions. “Oh my,” they think to themselves. “How on earth can I answer these apparent bullet-proof questions about God? Maybe we Christians should not be so confident with our answers after all.”
At the heart of the debate is the nature of God. Who is this God that Christians claim inspired the Scriptures, created everything else apart from himself out of nothing, and in the space of six consecutive days?
But also at the heart of the debate is the notion of logic and language. For example, an atheist declared recently in a discussion about the Law of Causality, that there were ‘uncaused effects.’ Now the Law of Causality merely states that every effect must have a sufficient cause. This is often expressed that everything that has a beginning has a cause. I prefer the first wording, though it really makes no difference. The meanings are similar.
I believe that Clark’s problems with empiricism that lead him to reject senses as untrustworthy can be answered by many of the subsidiary axioms of biblical revelation. How does he justify the validity of the law of contradiction? It is implicit in propositional revelation, he claims. For “David” to mean anything, it must also not mean “non-David.” He also goes to some length in replying to Nash, who asks him to demonstrate the legitimacy of deducing the mathematical equation, two plus two is four, from Scripture:
. . . Scripture does indeed teach a bit of arithmetic. Numbers, additions, and subtractions occur: after Judas hanged himself, there remained eleven disciples. Multiplication occurs and there are divisions by five, seven, and ten. If now, mathematics can be logically developed out of its principles, then mathematics can by “good and necessary consequence” be deduced from Scripture. (Festschrift, p. 468)
“How can man’s knowledge coincide with God’s? God knows the end and the beginning, and His sovereign purpose from all eternity in the creation of every fact. Man’s knowledge can never coincide with that. Not only does man have no ability to know anything exhaustively, he can never know anything creatively as God does, nor absolutely, nor in any other way have a coincidence of content. The difference between God and man cannot be bridged by the mind of man.
“But man the theologian wants to make an end-run around Scripture and Chalcedon. He wants some kind of “participation in the eternal,” or some kind of coincidence with the mind of God. If he is denied this, and is reminded of his creaturely status and knowledge, he reacts with dismay, as though the faith were denied. And indeed that faith is denied, the faith of the builders of Babel, who wanted to reach unto heaven and achieve a coincidence with the God they hated and denied. Not in his knowledge, being, politics, or anything else can man enter into the aseity or autotheotes of the three persons of the Godhead. …
“The mind of man cannot bridge that gap between God’s uncreated being and mind and itself. To know as God knows is impossible for man. Man knows as God ordains that man shall know, by His revelation in His word, and by His creation, which manifests His glory, order, grace, and law.
Rushdoony, R. J. (1994). Systematic Theology in Two Volumes: Volume I (189–190). Vallecito, CA: Ross House Books.