Thinking Matters Journal, Issue #1: Introducing Apologetics

It is with great pleasure and some pride that I’m able to announce the inaugural edition of the Thinking Matters Journal. We’ve been promising it for a while, and kept having to push it back due to other commitments, but we made a new year’s resolution to get it done by the end of January. This month, we made a real effort to hit that deadline, and we did.

This would have been absolutely impossible without the dedicated work of Jason Kumar and Stuart McEwing. Special thanks are due to them.

You can find the journal at Our main portal page at is also now live, and will continue to be updated with resources and links. Please email me if you know of any sites that should be added to one of the reference pages.

Bayesian Probability Theorem

Often heard in response to the arguments of historical apologetics, such as the claim that God raised Jesus of Nazareth from the dead, is the axiom ‘extraordinary claims require extraordinary evidence.’ People who use this line must be unaware this has been soundly refuted in current philosophical thought, or else persuaded to use irrational principles to satisfy the requirements of their ideological allegiances. After all, there are hundreds of extraordinary claims you come across each day, and yet have no trouble believing.

Consider the lottery reported last night on television as one such event. The chances of winning, or indeed any random sequence of numbers, is extraordinarily improbable, yet if it is true that extraordinary claims require extraordinary evidence, you should never believe it happened. Weighing the probability of the extraordinary event will swamp the reliability of the witnesses every time so that you should never believe it. Even if the programs reporting is 99.9% accurate.

This kind of thinking is really a popular hang-over of Hume’s problem with miracles, which has been thoroughly refuted. John Earman, the agnostic philosopher wrote the book called Hume’s Abject Failure, in which he argues as commonsensical as this principle sounds, it is demonstrably false. The problem that probability theorists have worked on is how one can establish highly improbable events. They realised that you also have to consider the probability that if the reported event would not have occurred that the event would have been reported as it is. 

For instance, what is the probability that the sequence of numbers reported as the lottery result, would have been reported had those numbers not been the correct result. In the case of the resurrection, what is the probability that if Jesus of Nazareth did not rise from the dead we would have the evidences of the empty tomb, the post-mortem appearances and the origin of the disciples belief, et cetera?

Thus an elegant way to assess highly improbable events was developed. The probability for hypothesis (H) on the given evidence (E) with respect to the general background knowledge (B), called Bayes’s theorem. 


How this works is you plug in values of >.5 for positive probability or <.5 for some negative probability. As the result moves towards 1 it is more likely and towards 0 it is less. In the numerator we have the intrinsic probability of H multiplied by H’s explanatory power, Pr(E/H). The intrinsic probability of H is the conditional probability of H relative to the background knowledge (B). The Pr(E/H) is the rational expectation of E given H is the case, again relative to the background knowledge (B). The background knowledge in both cases is tactically assumed. In the denominator the above product is added to the product of the intrinsic probability and explanatory power of the denial of H. If this latter product is 0 then the numerator and denominator are the same and yield a ratio equal to 1, meaning 100% probability.

Hume failed to appreciate the probability calculus which entails not only the general background knowledge of the way the world is, but also the probability that we should expect the given evidence had the proposed event not occurred. So it turns out that it could very well be the case that an extraordinary event would not require extraordinary evidence, if the evidence is highly unlikely to occur had the event not taken place. He confuses miraculousness with probability and infrequency with implausibility. That’s one reason why Hume’s argument against miracles is entirely fallacious. 

Richard Swinburne, the philosopher of science from Oxford University, after plugging in the values, gives the probability of Jesus’ resurrection from the dead as 97%. Now I’m not sure how he arrived at the values he plugged in, so I wouldn’t necessarily use Bayes’s Theorem for an analysis of philosophical hypotheses such as God raised Jesus from the dead. But I think enough has been said to show that extraordinary claims do not require extraordinary evidence.

The Historic Alliance Between Christianity and Science

January 15th, 2009, Robin Lloyd, Senior editor for wrote a popular news article discussing the Jesse Preston of the University of Illinois at Urbana-Champaign and her colleague Nicholas Epley of the University of Chicago psychological experiments on the trouble with reconciling Science and Religion. Her conclusions highlight the need for careful thought on integration.

When it comes to the ultimate questions, it’s really just one thing at a time, Preston says. People rarely think about these problems, however, so most people live their lives without paying much attention to how the universe started or how life began, Preston said. 1

Salman Hameed responds to her findings,

However, Hampshire College science historian Salman Hameed says Preston and Epley’s framing of the issues and interpretation of their findings are bound up in a particular view of science and religion known as the “conflict thesis.” Yes, sometimes particular scientific and religious claims conflict, but there are numerous examples of individuals, such as Isaac Newton, who saw no inherent conflict between their scientific and religious convictions, Hameed said.

The experiment’s results actually may reveal cultural forces – a specific way of thinking about science and religion – dating back to the 19th century, Hameed said, and these have shaped people’s thinking about science and religion. 

If society has been primed that science and religion have been in conflict, and that is the dominant narrative, then maybe all we are seeing is the effect of that priming, rather than the actual conflict,” Hameed said. Society and journalists like conflict stories because they grab attention, but science and religion interactions are more complex and defy over-simplistic oppositional categories, he said. 2

Reasons to Believe respond in their latest podcast of Science News Flash, 21 Jan 2009. There Kenneth Samples references the article of his, The Historic Alliance Between Christianity and Science 3. He serves as RTB’s Vice President of Philosophy/Theology.

Kenneth Samples gives four reasons why historically science and Christianity have been allies rather than enemies. Contrary to the claims of the “New Atheists” such as Richard Dawkins and Christopher Hitchens science and Christianity are not at war, but enjoy a healthier dialogue today than they ever have. The “Conflict thesis” suffers from a lack of support from historians and philosophers of science, and serves today as sensationalist fodder from the news media. 

Samples writes,

Conflicts between scientific theories and the Christian faith have arisen through the centuries, to be sure. However, the level of conflict has often been exaggerated, and Christianity’s positive influence on scientific progress is seldom acknowledged. I would like to turn the tables by arguing for Christianity’s compatibility with – and furtherance of scientific endeavor and arguing against the compatibility of naturalism and science. 4

The four reasons he supplies are as follows. 

(1) The intellectual climate that gave rise to modern science (roughly three centuries ago) was decisively shaped by Christianity.

(2) The principles underlying the scientific method (testability, verification/falsification) arise from the Judeo-Christian Scriptures. The experimental method was clearly nurtured by Christian doctrine.

While Christians have plenty of room to grow in the virtues of discernment, reflection, and vigorous analysis, the wisdom literature of the Old Testament consistently exhorts God’s people to exercise them, and the New Testament teaches the same message (see Col. 2:8; 1 Thes. 5:2 1; 1 Jn. 4: 1). These principles served as the backdrop for the emerging experimental method.5

(3) The philosophical presuppositions foundational to the study of science are rooted in Christian theism’s claims of an infinite, eternal, and personal creator who has carefully ordered the universe and provided man with a mind that corresponds to the universe’s intelligibility. This Christian schema served as the intellectual breeding ground for modern science.


Christian philosopher Greg L. Bahnsen argues not only that naturalism fails to justify its underlying presuppositions but also that naturalists illegitimately rest their scientific endeavors on Christian theistic principles. Naturalists borrow from Christianity. Consider this insightful observation by physicist and popular author Paul Davies:

People take it for granted that the physical world is both ordered and intelligible. The underlying order in nature-the laws of physics-are simply accepted as given, as brute facts. Nobody asks where they came from; at least they do not do so in polite company. However, even the most atheistic scientist accepts as an act of faith that the universe is not absurd, that there is a rational basis to physical existence manifested as law-like order in nature that is at least partly comprehensible to us. So science can proceed only if the scientist adopts an essentially theological worldview.6

One may wonder if science would have arisen had the dominant metaphysical views of the time been naturalistic and materialistic. Would naturalism have been able to sustain the scientific enterprise that Christian theism generated? The eminent Christian philosopher Alvin Plantinga gives his opinion: “Modern science was conceived, and born, and flourished in the matrix of Christian theism. Only liberal doses of self-deception and double-think, I believe, will permit it to flourish in the context of Darwinian naturalism.”7, 8


(4) The prevailing scientific notions of big bang cosmology and the emerging anthropic principle seem uniquely compatible with Christian theism.



1. Robin Lloyd, “God and Science: An Inner Conflict” (; Retrieved 27 Jan, 2009), 15 Jan 2009

2. Ibid. 

3. Kenneth Samples, “The Historic Alliance Between Christianity and Science” (; Retrieved 27 Jan, 2009), 1998.

4. Ibid. 

5. Ibid. 

6. As cited in Michael Bumbulis, “Christianity and the Birth of Science,” August 4, 1998, p. 21,

7. Alvin Plantinga, “Darwin, Mind and Meaning”, November 17, 1997, p. 8,

8. Kenneth Samples, “The Historic Alliance Between Christianity and Science” (; Retrieved 27 Jan, 2009), 1998.

The danger of intellectual compromise

In his massive work on postmodernism and evangelicalism, Don Carson drew attention to the perils and pitfalls of the Christian community’s navigation of pluralism. Although the Gagging of God is no longer as perhaps contemporary as it once was (his Christ and Culture Revisited or Becoming Conversant with the Emerging Church might be slightly more relevant) I still find myself returning to it as a source of invaluable insight and and clarity on broader cultural issues and theology. Today we might be witnessing a greater vibrancy and growth of Christian thinkers in philosophy, but I believe Carson’s words should still resonate with us:

In other words, I worry less about the anti-intellectualism of the less educated sections of evangelicalism than I do about the biblical and theological illiteracy, or astonishing intellectual compromise, among its leading intellectuals. Evangelicalism has many sons and daughters whose primary vocation is the life of the mind: writers, thinkers, scholars, academicians, researchers — in field after field. They are not inferior to other thinkers in similar fields. But with rare exceptions they have not made the impact they might have because their grasp of biblical and theological truth has rarely extended much beyond Sunday school knowledge. In the main, they think like secularists and bless their insights with the odd text or biblical cliché. They cannot quite be accepted by the secular guilds (unless of course they keep their mouths shut completely about heir faith), and they cannot revolutionize intellectual life in the West because they do not think like consistent Christians who take on the status quo and seek to replace it with something better.

Carson is the research professor of New Testament Studies at Trinity Evangelical Divinity School in Deerfield, Illinois, and the author of over 40 books on theology, hermeneutics, and Christian living .

Creation Ministries International Needs Help

Creation Ministries International Needs Your Help

Everyday at Creation Ministries International our PhD scientist & staff around the world are working to tear down the evolutionary stronghold and replace it with good science based on the accuracy and authority of the Bible. As a worldwide ministry with offices in seven countries, we stand ready with you to defend the faith, refute evolution, and advance the Gospel of Jesus Christ.

Now we ask for your help in getting this vital message out.

STEP ONE: Please follow the link below to invite all of your Facebook friends

STEP TWO: We need to find and equip pastors and churches– so please send us the name of your pastor and appropriate contact information and we can schedule a meeting at your church with no cost utilizing the best creation speakers in the world!

We send our thanks from our offices in Australia, Canada, New Zealand, Singapore, South Africa, the United Kingdom, & the United States.

Remaining in Him,

The Creation Ministries International Team

John M. Frame on Culture

For those who have been wrestling with the issue of culture recently (you know who you are!), John Frame has written a helpful piece on Christ and Culture. (This transcript appears in a revised form in the latest addition to his Theology of Lordship series, The Doctrine of the Christian Life).

“We have seen that culture is a mixed affair, the result of human sinful activity on the one hand, and God’s grace (common and special) on the other. Christians are not to leave culture alone or to limit their influence to the content of natural law. Rather they are to seek a transformation of culture through the whole Word of God.” (Doctrine of the Christian Life, pg 903).

HT to for the link!


Atheistic blogging of late has generated a lot of dry tinder for intellectual cannons. It goes to show, like Richard Dawkin’s book The God Delusion, that brilliant scientists can make miserable philosophers. Today I’m going to look at what scientism is, and why it’s clearly irrational.

As a methodological principle, if I want a definition for a philosophical term, I go to a philosopher. J. P. Moreland, distinguished professor of philosophy at Talbot School of Theology writes;

Strong scientism is the view that some proposition or theory is true or rational if and only if it is a scientific proposition or theory. That is, if and only if it is a well-established scientific proposition or theory that, in turn, depends upon its having been successfully formed, tested, and used according to appropriate scientific methodology. There are no truths apart from scientific truths, and even if there were, there would be no reason whatever to believe them…

[W]eak scientism allows for the existence of truth apart form science and are even willing to grant that they can have some minimal, positive rationality status without the support of science. But, science is the most valuable, most serious, and most authoritative sector of human learning. If strong scientism is true, then theology is not a rational enterprise at all and there is no such thing as theological knowledge. If weak scientism is true, then the conversation between theology and science will be a monologue with theology listening to science and waiting for science to give it support. For thinking Christians, neither of these alternatives is acceptable.1


Now strong scientism is self-refuting. That is, if strong scientism is true, then it is also false by its own merits. At base level, strong scientism is self-referencially incoherent. Things that are self-refuting are not merely false, but necessarily false. To dissect further, lets ask a couple of questions generated in response to the recent statement, “If you don’t use honest process like science you don’t get to the truth.2

Is the statement “If you don’t use [an] honest process like science you don’t get to the truth,” true? If it is not true then it is false. If it is true then that statement, which itself was not arrived at by a scientific process, breaks its own rule. This is a philosophical claim about science methodology, and not a scientific claim established by the scientific process. Therefore, the statement is false either way.

Perhaps what was meant is, “If you don’t use [an] honest process like science you won’t be able to know if the conclusion is the truth or not.3

This rephrasing does avoids self-refutation, but leaves the ‘honest process of science’ self-defeating. As a philosophical statement about how we know truth and not scientific one, we have no way of knowing if the statement itself is true or not. If it is false then we shouldn’t believe that science is the only process by which we attain truth. If it is true, then as the statement did not come via the scientific process, we cannot know it is true.

Perhaps a more generous reading of the modified statement is required, and “an honest process like science” means we should include other methods such as logic, philosophy and experience as ways one can discover and know truth. If that is the case this would severely undermine the charge of scientism displayed by atheistic bloggers and open the door once again for a two way dialogue on God’s existence. Alternatively, perhaps it means to exclude dishonest processes4 such as those supposedly employed by Christian apologists. But as apologists use philosophy and other truth gathering methods that effectively drains away all meaning from the point originally being made (which was it is illegitimate to plug God into a gap where there is scientific ignorance5), and the task of the apologist’s detractor remains the same – to show that the method or argument used in garnering specific truths is faulty.


There are two considerations that equally undermine both strong scientism and weak scientism.


It does not adequately allow for the task of justifying the assumptions necessary for science’s success. The practice of science relies upon some necessary presuppositions that themselves need to be supported. Science cannot be strung up on thin air.

But the conclusions of science cannot be more certain than the presuppositions it rests on in order to reach those conclusions. Thus it is philosophy, and not science, which is in a better position and is the far stronger candidate for being the paradigm of rationality.

A list of the assumptions is given here;6

(1) The existence of a theory-independant world

(2) the orderly nature of the external word

(3) the knowability of the external world.

(4) the existence of the truth

(5) the laws of logic

(6) the reliability of our cognitive and sensory faculties to serve as truth gatherers and as a source of justified beliefs in our intellectual environment

(7) the adequacy of language to describe the world

(8) the existence of values used in science (honesty)

(9) the uniformity of nature and induction

(10) the existence of numbers.


Truth can be known apart from the scientific process. There are many fields outside science and wholly apart from the scientific process that provide us with true, rationally justified beliefs. Highlighted here are five of these areas.

First, logical and mathematical proofs.

  • 1 + 1 = 2
  • Laws of inference, (e.g., modus ponems, disjunctive syllogism)
  • Law of non-contradiction, (e.g., you cannot be man and non-man at the same time and the same place)

Second, metaphysical truths.

  • There are other minds that are not my own,
  • The past was not created five minutes ago with the appearance of age.

Third, ethical beliefs or value judgements of right and wrong.

  • It is wrong to torture babies for fun.
  • Feeding the poor is a virtue.
  • Kicking orphans and widows is wicked.

Fourth, there are aesthetic judgements,

  • A sunrise beaming through a morning fog is beautiful.
  • The glacial lake surrounded by ice-capped mountains is inspiring.
  • Mozart’s second symphony is sublime.

Fifth, certain propositions.

  • Red is a colour.
  • I am now thinking about science.

All these examples are well within our rational rights to believe, though we have no confirmation of their truth from science. In fact, one hundred years from now all these will still be perfectly rational and hold greater epistemic status than certain scientific theories. For instance the metaphysical truth that I am not only a brain being stimulated in a vat, or that absolute truth exists, hold greater warrant than the science that says the plane I’m on will successfully supersede the law of gravity according to the laws of aerodynamics, or the major cause of global warming the human carbon footprint.


Considering the above it becomes evident that scientism, in either its weak and strong form, is a hindrance to science. It is also anathema to truth and bears a striking resemblance to the dogmatism the advocates of scientism wish to avoid. It is for this reason that scientism is considered among philosophers to be a bankrupt system of thought and avoided at the cost of rationality. Nicholas Rescher, University Professor of Philosophy at the University of Pittsburgh, concludes;

The theorist who maintains that science is the be-all and end-all — that what is not in science books is not worth knowing — is an ideologist with a peculiar and distorted doctrine of his own. For him, science is no longer a sector of the cognitive enterprise but an all-inclusive world-view. This is the doctrine not of science but of scientism. To take this stance is not to celebrate science but to distort it by casting the mantle of its authority over issues it was never meant to address.7


1. J. P. Moreland, Love God With All Your Mind (Colorado Springs: NavPress, 1997), P. 144-145.

2. Ken Perrott, “Fine tuning of the universe?”, 75., (; Retrieved 13 Jan, 2009)

3. Heraclides, “‘Scientism’ in the eyes of the beholder”, 14., (; Retrieved 13 Jan, 2009)
4. Ibid., 23.

5. Ken Perrott and James, “Fine tuning of the universe?”, 70, 72., (; Retrieved 13 Jan, 2009). See also Stuart McEwing, “The “god-of-the-gaps” argument”, 6, 7, 11, 17., (; 28 Dec, 2008)

6. J. P. Moreland and William Lane Craig, Philosophical Foundations for a Christian Worldview (Downers Grove, Illinois, InterVarsity Press: 2003) p. 348.

7. Nicholas Rescher, The Limits of Science (Berkley, University of California Press: 1984).

Ehrman and Williams discuss the reliability of the New Testament

Last weekend, Bart Ehrman and Peter Williams discussed the textual reliability of the New Testament on the popular UK radio show, Unbelievable. Explaining the science of textual criticism and successful bookselling aren’t things you’d expect to go hand in hand. Against unlikely odds, prominent Biblical scholar and professor of religious studies at the University of North Carolina, Bart Ehrman has managed to couple the two. His fizzing cherry-bomb of a bestseller, Misquoting Jesus, has brought about an unlikely level of interest in the study of the genealogy of the Biblical documents across broad audiences. However, it must be pointed out that Ehrman’s success does not chiefly rest in his exploration of the origin and transmission of the Biblical texts. While he has an undeniable knack for translating a subject known for it’s aridity into simple and accessible terms, Misquoting Jesus has catapulted to the top of celebrated booklists because of the claims put forward by Ehrman. In the book, Ehrman controversially argues that the existence of so many variant copies of the New Testament manuscripts have cut us off from the actual words of Jesus and prevent us from trusting the Bible as God’s authoritative revelation.


This episode of the radio show has Ehrman explaining and defending some of the claims of his book with another Biblical scholar Peter Williams. Williams is the head of the Tyndale House at Cambridge and the senior lecturer in Biblical Studies at the University of Aberdeen. If you’re unfamiliar with textual criticism or the broader controversy surrounding Ehrman’s book, this may be a good introduction to the debate.

Stream the discussion online from the Unbelievable site or download the full episode (about 28MB in size). You can subscribe to the podcast here.

This weekend, Ehrman will return to the show to discuss God and the problem of evil with eminent philosopher of religion, Richard Swineburne.

(Source: JT and Denny Burk)

Coming debates

What’s so great about God?

Christopher Hitchens and Dinesh D’Souza, University of Colorado, 26th January, 2009.

Christopher Hitchens and William Lane Craig, Biola University, 4th April, 2009.

What makes a good argument?

Edited by by Dominic Bnonn Tennant: 07/01/2009

An Introduction to Logic

I often tell people that the most useful and fundamental tool in the apologist’s tool-kit is logic. However, it’s depressing how often I see basic logical mistakes being made. Even more depressing is when an opponent or detractor of an argument actually thinks he or she is making a good point, when a basic mistake is obvious. To help with avoiding this, I’m going to lay out a few ground rules for debating: what logic is, and how to use it.

Logic is the study of the rules for right thinking. This is often not properly understood. People tend to use “logic” as a popular synonym for “common sense,” but it is actually a highly technical sub-discipline of philosophy, akin to mathematics. It’s a discipline that itself has many sub-disciplines, and like mathematics, it’s very easy to understand the basics and to use them correctly. For now, we’ll just be surveying basic deductive logic, by asking the question: what makes a good argument?

For our purposes, I’m taking a good argument to be one which is persuasive to a broad range of people. It is one which would persuade a reasonable person, and ideally even an unreasonable person. There are four criteria which make a good argument.

I. It must be formally valid

Formal validity means that the conclusion of the argument follows necessarily from its premises. Such an argument can be structured into a syllogism, which is a way of writing it with its various premises, and a conclusion, as in the examples below. If an argument breaks one of the rules of inference, it is formally invalid. We’ll look at the nine essential rules of inference, first using proper notation, and then using plain language with an example. Leibniz, the German philosopher who formulated many of these rules and gave them their notation, believed that all thought was constructed from these simple rules.

1. Modus ponens

Modus ponens is Latin. It means “the mode which affirms”. Knowing the English translation makes it very easy to follow:

  1. P ? Q
  2. P
  3. Q

In plain English: if P, then Q; P, therefore Q. “P” and “Q” represent propositions, so it’s helpful to substitute in simple phrases for them, to get a better idea of what the rule is saying. For example, let P mean “it is raining”, and let Q mean “the ground is wet”. So:

  1. If it is raining, then the ground is wet.
  2. It is raining.
  3. Therefore, the ground is wet.

As you see, this is really a very simple and obvious rule—as you’ll find that all the fundamental rules of logic are.

2. Modus tollens

Like modus ponens, modus tollens is also Latin. It means “the mode which denies”. Again, this gives a helpful clue as to its form:

  1. P ? Q
  2. ¬ Q
  3. ¬ P

In plain English: P implies Q; not Q, therefore not P. Substituting in some propositions:

  1. If it tastes sweet, then I like it.
  2. It don’t like it.
  3. Therefore, it doesn’t taste sweet.

3. Hypothetical syllogism

  1. P ? Q
  2. Q ? R
  3. P ? R

If P implies Q, and Q implies R, then P implies R.

  1. If it is cheese, then it is delicious.
  2. If it is delicious, then I want to eat it.
  3. Therefore, if it is cheese, then I want to eat it.

4. Conjunction

  1. P
  2. Q
  3. P ? Q

If P, and if Q, then P and Q.

  1. I have chocolate.
  2. I have cheese.
  3. Therefore, I have chocolate and cheese.

5. Simplification

  1. P ? Q
  2. Q

If P and Q, then Q. This isn’t a trick rule; you shouldn’t read it to be excluding P by stating the conclusion Q. It’s just saying that if two things are true, then one of those things is true. Of course, the other is also true, so we can equally say, if P and Q, then P. Both are valid simplifications of the same premise.

  1. I like chocolate and I like cheese.
  2. Therefore, I like cheese.
  1. I like chocolate and I like cheese.
  2. Therefore, I like chocolate.

6. Absorption

  1. P ? Q
  2. P ? ( P ? Q )

If P implies Q, then P implies both P and Q.

  1. If it is raining, then the grass is wet.
  2. If it is raining, then it is raining and the grass is wet.

7. Addition

This is also known as the disjunction introduction, since it introduces disjunctions (“and/or” statements).

  1. P
  2. P ? Q

P, therefore P or Q. In other words, given some proposition P, either P is true, or some unrelated proposition Q is true. The truth of Q doesn’t exclude the truth of P, though typically it is assumed.

  1. The sun rises in the east.
  2. Therefore, the sun rises in the east, or I have a secret identity as a superhero.

8. Constructive Dilemma

  1. ( P ? Q ) ? ( R ? S )
  2. P ? R
  3. Q ? S

If P implies Q, and R implies S, P or Q is true; so R or S is true.

  1. If Yvette comes along on the trip, then Jim will be happy; and if Jim goes on the trip without Yvette, then he will be lonely.
  2. Either Yvette comes along on the trip or Jim goes on the trip without Yvette.
  3. Therefore, either Jim will be happy or he will be lonely.

9. Disjunctive syllogism

This is basically an “either/or” statement:

  1. P ? Q
  2. ¬ P
  3. Q

P or Q; not P, therefore Q. Of course, the converse is also true: P or Q; not Q, therefore P.

  1. I am allowed either two plain biscuits or one chocolate biscuit.
  2. I choose to eat the one chocolate.
  3. Therefore, I don’t choose to eat the two plain.

II. It must be informally valid

The second of the criteria of a good argument is informal validity. Being formally valid is not enough; it must also not commit any informal fallacy. There are many kinds of informal fallacies—far too many to list here. However, I’ll cover the eight of the most common. When an argument commits any of these fallacies, it is informally invalid.

1. The strawman

This is misrepresenting your opponent’s position in some way—either by caricaturing it, or assuming that he holds to the most vulnerable possible variant of it—and then arguing against that misrepresentation as if it were his actual position. For example:

      Person A: “Life got here by creation.”


    Person B: “That’s impossible because the earth could not possibly have been created in six 24-hour days.”

2. Begging the question

Arguing in a circle and providing no reason for accepting a premise in your argument, other than the conclusion of the argument itself.

      Person A: “I know that God exists because the Bible says He does.”


      Person B: “How do you know the Bible is telling the truth?”


    Person A: “Because the Bible was written by God.”

3. The genetic fallacy

Arguing for or against some belief based on the origin of that belief.

  • Because of our fear and ignorance of nature we invented God. Therefore he does not exist.
  • This fellow often produces shoddy research, so his latest paper should be dismissed.

4. Argument from ignorance

Arguing that a belief is false because there is insufficient evidence for it.

  • No one can disprove the existence of God. Therefore, God exists.
  • There’s no evidence that the Red Sea was ever parted. Therefore, the account in Exodus is a myth. (Notice, though, that an argument saying that there is evidence that the Red Sea was not ever parted would not be fallacious.)

5. Equivocation

Using a word or category in such a way that it has more than one meaning.

  1. Margarine is better than nothing.
  2. Nothing is better than butter.
  3. Therefore, margarine is better than butter.

6. Amphiboly

Formulating a premise in such a way as its meaning is ambiguous.

  • No food is better than our food.

7. Composition

Inferring that a whole has a certain property because all of its parts have that property.

  • Every part of an infinite past can be traversed. Therefore, an infinite past can be traversed.
  • Every tile on the floor was cheap, therefore the tiled floor is cheap.

8. Ad hominem.

Attacking the person and not the argument (Latin: “at the man”).

  • What he says can’t be correct because he’s a religious nut.
  • Calvinism is awful because John Calvin burned Servetus at the stake. (Notice how this example also constitutes the genetic fallacy.)

Is this a good argument?

  1. Either I am crazy, or I am dead.
  2. I am not crazy.
  3. Therefore, I am dead.

This disjunctive syllogism is both formally and informally valid, making it logically valid. But obviously this not a good argument. On reflection premise one is rather spurious. Why should anyone accept the dilemma presented there? There is also cause to doubt premise two. Therefore, logical validity is not all that is required to make a good, convincing argument. A good argument requires something else.

III. It must have true premises

The third criterion is that a good argument must have true premises. When an argument is formally and informally valid and has true premises, it is sound. But if it is invalid, or it has false premise, it is unsound. When an argument is sound the conclusion follows necessarily and inescapably from its premises. It doesn’t matter if you don’t like it. If you disagree, then you are wrong. When an argument is sound the conclusion is true. Of course, if we don’t know that some premise is true, then we can’t know if the argument is sound. But not knowing the truth of a premise does not make the argument unsound.

You’ll remember that we defined a good argument as one which will persuade a broad range of people, convince a reasonable man and hopefully even an unreasonable man. When an argument is sound, does this mean it is a good argument? This brings us to our final criterion.

IV. Premises more probable than their contradictories

When constructing an argument it would be a tall order indeed if we had to prove the truth of every premise. If that were the case we would be lost in utter scepticism, for we would have to prove the premises of the arguments for the premises of the argument, and the premises of those arguments backwards ad infinitum.

To save us from scepticism a good argument must have premises which are at least more probable than their contradictories. In other words, a premise should be more plausibly true than false. We need not know for certain a premise is true; we need only know that the alternative is less likely.

Obviously there are many differing opinions on many differing subjects, and we live in a very divergent and contrary world. The most powerful arguments will therefore be those structured on premises which are widely accepted and are the hardest to deny. The strength of an argument will depend on the strength of its premises.

Now, plausibility is a person-dependent notion, so in cases of disagreement we need to dig a little deeper to see what reasons we have for accepting or rejecting a premise. When we do, we may find that we have made the mistake—but we also may find that our opponent’s rejection is based on misinformation, ignorance of evidence, or a fallacious objection. Thus we may be able to persuade the other by giving better evidence, information, or gently correcting their error.

Frustration with USA shipping

I have on various occasions wanted to purchase products from the USA but have found that either New Zealand is not on the list of shipping destinations, or the price of shipping is simply out of this world. Today I came across another such case.

Here is a small booklet titled Who’sAfraid of the Multiverse? by Jeff Zweerink (68 pages; $4USD to buy). I added two of these to the cart and went to the checkout … only to find:

United States Postal Service
Priority Mail International – $ 27.25
Express Mail International (EMS) – $ 32.25

Federal Express
International Priority – $ 66.61

Wow, that’s about $50 NZD minimum shipping charge. Ouch :-( !

I don’t want to bash Christian ministries that are often overworked and understaffed, but I really do think that USA Christians (generally) need to be more globally focussed and a little less focussed on the US market as if it is the only one that exists.

In fact, many non-US Christians are desperate for materials but cannot acess them easily or at reasonable price. Is this really helpful in the big picture?

Even a pay-for PDF download option for non-US customers could be useful at times.