August 06, 2015

Reductio ad absurdum

Photo: Jurassic World (2015)
By Hendrik van der Breggen
The Carillon, August 6, 2015
Reductio ad absurdum
Reductio ad absurdum is an argument strategy that employs logic to tease out the truth that another argument or claim is flawed. How? By reducing it to absurdity.

Let's look at this argument strategy in general terms, and then let's illustrate with a couple specific examples.

In a reductio ad absurdum argument, we assume, temporarily for the sake of argument, that the view under investigation is true. We approach the view in question with the attitude, "Okay, let's say it's true. What follows?" If the logical consequences of the view's assumed truth are false or logically contradictory, then it follows that the view under investigation is false or at least deeply problematic.

Here is an example from contemporary popular moral thought.

Consider the view that ethics is mere feeling, i.e., what's right and wrong is fundamentally a matter of subjective opinion or taste—there is no real right or wrong.

Let's say this is true, for the sake of argument. What follows logically?

If ethics is mere feeling, i.e., mere subjective opinion or taste, then right and wrong mean "I like" and "I don't like," respectively. Ethics becomes essentially similar to our attitudes to, say, food.

Just as I like chocolate ice cream rather than vanilla, you like vanilla rather than chocolate. No big deal. We're both right.

Cake: yum! Kale: yuck! Good: yum! Bad: yuck! This is the ethics-is-mere-feeling view.

But if the ethics-is-mere-feeling view is true (as we'll assume for the sake of argument), then another claim follows logically as true: just as Jane likes helping people and seeing them flourish, Joe likes torturing people and seeing them writhe in pain. So, if it's true that ethics is mere feeling, then Jane and Joe are both right ethically. No big deal.

Surely, though, that Jane and Joe are both right is clearly false (we know this via moral-rational insight). Hence, the assumption that ethics is mere feeling is flawed.

Here is another example from contemporary popular metaphysical thought (metaphysics has to do with the reality of being).

Let's say that personal identity, i.e., what I am, is wholly a personal matter—again, a matter merely of subjective feeling. My feelings about myself and my identity are trump.

Bruce (Caitlyn) Jenner basically holds this view. He feels he is a woman so he is a woman—and so he has had plastic surgery to "feminize" his face and throat, had hormone therapy for growth of breasts, and may yet undergo genital surgery to remove his testicles plus use his penis to construct a "vagina."

But if the view that my feelings about myself and my identity are trump is true, what follows?

It means that we must accept the claims of "otherkin" as true. Otherkin are people who self-identify as—i.e., who believe they actually are, at least in part or wholly—non-human. They believe they are cats, foxes, dragons, etc. If feelings are trump, then they are non-human in fact.

Moreover, it means we must accept the claim of Adrian Van Oyen, who in a YouTube "coming out" video, claims to be a dinosaur. Yes, a dinosaur. And, according to Van Oyen, if you don't accept him for who he is, you are "transdinophobic."

(Note: Van Oyen's two-minute video is a stunt, ending with an image of a "facepalm" to the forehead; nonetheless, it makes an insightful philosophical point.)

Surely, however, the alleged truth of the thesis that my feelings about myself and my identity are trump lands us logically into obvious absurdities and falsehoods. Regardless of what a man feels, he is in reality not a dinosaur, nor a cat, nor a woman.

Feelings are not trump. Reductio ad absurdum.

Objective truth and reality are trump.

(Hendrik van der Breggen, PhD, is associate professor of philosophy at Providence University College.)


A. Here are a couple  interesting reductio-ad-absurdum-related bits located here because of space limitations in the main body of my column:

1. If my feelings about myself and my identity are trump, then we should also accept the claims of the "transabled." The transabled are people who feel that they are imposters if their body is in full working order, so they seek to amputate a limb or otherwise mutilate/ disable themselves. But the truth is that you are not in fact an imposter if your body is in full working order. Again, the alleged truth of the thesis that my feelings about myself and my identity are trump lands us logically into obvious absurdities and falsehoods.

2. The Bible is no stranger to logic (which makes good sense because God is the Logos). In fact, the reductio ad absurdum is employed in the New Testament. Paul preaches the resurrection of Jesus (which he and others know to be true) and Paul addresses those who say there is no resurrection of the dead. He argues "if there is no resurrection of the dead, then not even Christ has been raised" (1 Cor. 15:13). But Paul adds that he testifies to Christ being raised: "Christ has indeed been raised from the dead" (1 Cor. 15:20a). That is, Paul and others know this to be true. D.J. Hill, in New Dictionary of Apologetics, concludes: "So, Paul shows that the assumption that there is no resurrection leads to the contradiction that Christ has both been raised and not raised from the dead." In other words, in view of the known fact that Jesus was in fact raised from the dead, the claim that there is no resurrection reduces to the absurd.

B. For further discussion of reductio ad absurdum arguments, see:

1. Julian Baggini & Peter S. Fosl, The Philosopher’s Toolkit: A Compendium of Philosophical Concepts and Methods, 2nd edition (Oxford: Wiley-Blackwell, 2010), 121-122.

2. D. J. Hill, “Reductio Ad Absurdum,” in New Dictionary of Christian Apologetics, edited by W. C. Campbell-Jack & Gavin McGrath (Downers Grove, Illinois: IVP Academic, 2006), 602-603.

July 23, 2015

Crusades versus Christianity

Photo: Kingdom of Heaven (2005 film)
By Hendrik van der Breggen
The Carillon, July 23, 2015

Crusades versus Christianity

Many persons object to Christianity because of the horror of the Crusades (c. 1096-1291). I think this objection can be diffused with four points.

First, contrary to popular opinion, the Crusades were not acts of unprovoked aggression against the Islamic world. The Crusades were in fact a belated response to centuries of Muslim military aggression. As Steve Lee points out in Apologetics Study Bible for Students, "Christian Europe had to defend itself or be overcome by Islamic invasion."
Second, though much evil occurred during the Crusades, the Crusades weren't as bad (comparatively speaking) as many think. Historical perspective is helpful. Compare the goings-on of some officially atheist societies with that of some predominately Christian ones.

The major horrors of Christian Europe—i.e., the Crusades and the Spanish Inquisition—amounted to the killing of 1.4 million people. This is terrible and wrong, to be sure.

Significantly, however, the following body count under two officially atheist regimes should also be noticed: China 80,170,000; USSR 61,911,000. Total: over 142 million!

Two officially atheist regimes are responsible for 100 times as many killings than predominantly Christian societies!

(Note: The above numbers are from Rudolph Rummel, a Nobel Peace Prize nominated political science professor at U of Hawaii. Rummel's specialty is the study of genocide and deomcide.)

Third, Christianity's track record is far from wholly negative. Pros—not just cons—should be considered.

Near the end of his seven-volume A History of the Expansion of Christianity (Harper, 1945), Yale historian Kenneth Scott Latourette concludes as follows:

"[Christianity] has been the most potent force which mankind has known for the dispelling of illiteracy, the creation of schools, [and] for the emergence of new types of education."

Latourette adds: "The universities...were at the outset largely Christian creations.... Music, architecture, painting, poetry, and philosophy have owed some of their greatest achievements to Christianity."

Latourette continues: "Democracy as it was known in the nineteenth and twentieth centuries was in large part the outgrowth of Christian teaching. The abolition of Negro slavery was largely due to Christianity. So, too, were the measures to protect the Indians against exploitation of the whites.... The elevation of the status of women owed an incalculable debt to Christianity...."

In fact, according to Latourette, "No other single force has been so widely potent for the relief of suffering brought by famine and for the creation of hospitals and orphanages."

(Recent social-religious historical work by Alvin Schmidt, Rodney Stark, Vishal Mangalwadi, and others confirms Latourette's work.

Fourth, whether the central doctrines of a worldview are true doesn't depend on the failure of adherents to live up to that worldview's moral standards.

For example, if the claim that the God-man Jesus in fact lived, died, and resurrected is true (as I believe it is), then it is not made false by my evil actions. My evil actions only show that I'm a lousy follower of Jesus.

Moreover—and significantly—whereas my wicked behaviour is condemned by Jesus' teachings, Stalin's and Mao's wicked behaviour—i.e., their murder of millions—is not condemned by their philosophies.

Stalin and Mao acted consistently with the Marxist-Leninist principle that a utopian end sometimes justifies dastardly means (such as murdering anyone who disagrees). The Crusaders and Inquisitors, however, when they did evil, acted inconsistently with Jesus' command to love others.

Yes, much evil occurred during the Crusades. But these evils are not inherent to Christianity. They are due to people who claimed to be Christians (and many weren't Christians) but didn't live up to Jesus' teachings. Christians who sin make Christianity unattractive, not false.

The objection to Christianity's truth based on the Crusades is therefore weak.

To recap, the Crusades were a response to Islamic aggression, not an unprovoked attack; the Crusades were, compared to the evils of officially atheist regimes, not as bad as many believe; Christianity has been a huge force for good in the world; the truth of Christianity centers on Jesus Christ—God come to earth as a human being—not the failings of His followers.

(Hendrik van der Breggen, PhD, teaches philosophy at Providence University College.)

Further reading/ listening:

  • Paul F. Crawford, "Four Myths about the Crusades"
  • Clay Jones, "The Truth about the Crusades": blog post and interview
  • Michael Karounos, Movie review: Kingdom of Heaven
  • July 09, 2015

    The good of disagreement

    By Hendrik van der Breggen
    The Carillon, July 9, 2015

    The good of disagreement

    Disagreement can be tough, but also good. Disagreement, when done well, can develop intellectual virtues.

    In general, a virtue is an excellence of character, where character is a disposition (tendency/ habit of mind) to act in accordance with what's true and good.

    The Apostle Paul famously set out the theological virtues: faith, hope, and love (the greatest being love). Prior to Paul, Plato presented these virtues of the soul: wisdom, courage, temperance, and justice. Augustine later "baptized" Plato's virtues, adding them to (and explaining in accordance with) Paul's list. Other well-known virtues include kindness, patience, gentleness, and self-control.

    Properly understood, virtues are centered in God's holiness and love.

    What about intellectual virtues? Enter: Princeton University philosopher Robert P. George. Much of what follows is gleaned from Professor George's contribution to "The Cost of Freedom: How Disagreement Makes Us Civil," a conversation between George, Cornell West, and Rick Warren.

    As a preface to understanding intellectual virtues, George prioritizes truth and emphasizes, following John Henry Newman (1801-1890), that truth should be pursued for its own sake. Knowledge of truth, though it has instrumental value, is an intrinsic good (i.e., it's good, period).

    Then, following John Stuart Mill (1806-1873), George points out that freedom of thought and freedom of expression are essential conditions of truth-seeking. (We could be mistaken, so such freedom allows us to learn from others.)

    George also points out that the enterprise of truth-seeking (especially in the academic realm) trades in "a currency consisting of reasons and arguments."

    Significantly, then, to excel at truth-seeking we should cultivate personal character traits conducive to achieving knowledge of truth. These are the intellectual virtues.

    Here are three such virtues.

    1. Commitment. In our discussions and debates, we should commit ourselves to discerning truth. Truth is (as mentioned) an intrinsic good. But sometimes it takes work to discover. And sometimes it's unpopular. Commitment is a love of truth, which calls for tenacity and courage.

    Also helpful is proficiency in logic and critical thinking.

    2. Friendship. In our efforts at discerning truth with our interlocutors, we develop what George calls the "bond of truth-seeking." Humans are relational (not merely intellectual) beings, so disagreement—good disagreement—provides opportunity to develop personal relationships rooted in disagreement yet stronger than the disagreement.

    How so? By striving in a common project to arrive at truth together. By listening to each other and learning from each other, even in the midst of stress. This enriches us and ennobles us.

    The bond of truth-seeking takes truth to be more important than agreement. Thereby this bond provides a ground for ongoing friendship in spite of disagreement.

    3. Humility. We are fallible creatures. Our reason is imperfect, and our sin/ self-centeredness darkens the intellect and weakens the will. We should remember this.

    But humility, according to George, doesn't mean we should give up on reason and knowledge of truth. Nor should we conform to cultural orthodoxy. Rather, we should acknowledge our limitations and enter into respectful dialogue plus careful, fair-minded, truth-seeking study.

    We should listen to others and learn from others, so those others, if not mistaken, will correct us—i.e., teach us. Humble truth-seekers will welcome this.

    On the other hand, if we are right—which we sometimes are—we shouldn't feel superior. Nor should we shut down our conversations with those who disagree. Rather, we (again) listen. Thereby, says George, our interlocutor teaches us "why reasonable people of good will can disagree."

    As a bonus, if we still have the better reasons after running the gauntlet of criticism, we "now have deeper understanding of truth because we have knowledge that arguments against it fail."

    Knowledge of truth can be held humbly, in other words. And further argument and its accompanying friendship, the bond of truth-seeking, can help us draw nearer to truth and help us flourish socially.

    We live in a world in which many people disagree over much. Let's encourage the development of virtue—intellectual virtue included.

    (Hendrik van der Breggen, PhD, teaches philosophy at Providence University College.)

    For further reading: