Dialectic: The Second Art of the Trivium

Introduction: What is dialectic? What is logic?

The second liberal art is logic or dialectic. Dialectic typically refers to the practice of precise discussion, using a question and answer format with facts or apparent facts, to explain or get at the truth. It has another, less academic, use I’ll explain later. Logic is a more narrow term, referring to the form of correct argument rather than the whole process. In classical school literature, you’ll see the two words used interchangeably (I will as well), this has classical precedent. For instance, the stoics tended to use the word logic to refer to argument, monologue, persuasion, theory, and several other domains. The best definition for logic/dialectic is the art of reasoning for the purpose of discovering or demonstrating the truth. And so logic involves the study of the forms of argument as well as specific arguments. But why study dialectic? Isn’t it easier to just go with gut feelings or go a long to get along?

Dialectic Protects Us From Pathological Thinking

An alarming trend in education today is the reinforcement of pathological thinking patterns by professors who will not expose students to material that is challenging to their worldview (if the worldview is of a certain sort, anyhow). Jonathan Haidt and Greg Lukianoff explain this ugly trend:

There’s a saying common in education circles: Don’t teach students what to think; teach them how to think. The idea goes back at least as far as Socrates. Today, what we call the Socratic method is a way of teaching that fosters critical thinking, in part by encouraging students to question their own unexamined beliefs, as well as the received wisdom of those around them. Such questioning sometimes leads to discomfort, and even to anger, on the way to understanding.


But vindictive protectiveness teaches students to think in a very different way. It prepares them poorly for professional life, which often demands intellectual engagement with people and ideas one might find uncongenial or wrong. The harm may be more immediate, too. A campus culture devoted to policing speech and punishing speakers is likely to engender patterns of thought that are surprisingly similar to those long identified by cognitive behavioral therapists as causes of depression and anxiety. The new protectiveness may be teaching students to think pathologically.

Notice the claim in bold. Our dominate institutions of knowledge and reasoning are training young people to be threatened by claims which contradict their beliefs. Put more simply, people are learning to be offended by disagreement. One of the primary reasons to learn logic is that it can train us to distance ourselves from our beliefs and the claims of others and to ask whether or not they are supported by evidence or at least coherent with one another.

Logic Trains Us in Virtue

Another reason to learn logic is that logic is training in virtue. Dallas Willard explains that:

[Logic] requires the will to be logical, and then certain personal qualities that make it possible and actual: qualities such as freedom from distraction, focused attention on the meanings or ideas involved in talk and thought, devotion to truth, and willingness to follow the truth wherever it leads via logical relations. All of this in turn makes significant demands upon moral character. Not just on points such as resoluteness and courage, though those are required. A practicing hypocrite, for example, will not find a friend in logic, nor will liars, thieves, murderers and adulterers. They will be constantly alert to appearances and inferences that may logically implicate them in their wrong actions. Thus the literary and cinematic genre of mysteries is unthinkable without play on logical relations.


Those devoted to defending certain pet assumptions or practices come what may will also have to protect themselves from logic. All of this i, I believe, commonly recognized by thoughtful people. Less well understood is the fact that one can be logical only if one is committed to being logical as a fundamental value. One is not logical by chance, any more than one just happens to be moral. And, indeed, logical consistency is a significant factor in moral character. That is part of the reason why in an age that attacks morality, as ours does, the logical will also be demoted or set aside–as it now is.

Again, note the bold. Willard claims that since being logical requires that one be devoted to truth, free from distraction, and concerned with meaning, that those who only want to defend pet ideas will find no friend in logic. And we live in a world wherein people seem to have no plan to examine their lives as Socrates recommended. I’ve known Christians, atheists, democrats, republicans, logic professors, men, women, adults, and children who approach life in this unexamined way.

Of course, I’m not quite making an argument here. But I will:

  1. True beliefs are good and false beliefs are bad.
  2. Logic helps us reject false beliefs are discover true ones.
  3. Therefore, logic helps us discover what is good.

The steps in the argument above would be readily accepted by most.

Further Reflections

In short, logic or dialectic is the skill of thinking things through. There are several varieties. Logic can be taught in a symbolic or mathematical form or a propositional (sentence based) form. Similarly, logical reasoning can be divided up in terms of the form taken in the reasoning. One can utilize deductive reasoning or inductive reasoning. These can simplified in this way:

  1. Deductive reasoning is reasoning such that true statements are arranged in such a way as to yield a necessarily (this means it cannot be any other way) true conclusion.
  2. Inductive reasoning is based on probabilities or what may or is likely or unlikely to be the case.

Either of these logical forms requires that you have three things in order to have a complete syllogism (a series of statements leading to a conclusion):

  1. Premises – these are the starting facts of a syllogism.
  2. Inferences – these are statements moving beyond any of the individual premises by relating them to one another or moving beyond them in a way which follows the rules of thought (to be discussed later).
  3. Conclusion – this is the final inference in the series.

An example might look something like this:

  1. The sum of the angle measurements in a triangle is 180 degrees. (Premise: Statement)
  2. Therefore, the sum of the angle measurements of two triangles is 360 degrees. (Premise: Inference from point 1)
  3. All quadrilaterals can be divided into exactly two triangles.
  4. Therefore, the sum of the angles in a quadrilateral is 360 degree. (Conclusion: inference from statements 1, 2, and 3).

Though a comprehensive overview of logical reasoning is not possible in a blog post, I do want to mention arguing by analogy. Argument by analogy is looking at a known relationship, such as that between water and its constituent elements: hydrogen and oxygen and generalizing a principle from this relationship and using it to make a provisional inference concerning an unknown relationship:

  1. Water is made up of hydrogen and oxygen atoms. (Original Case)
  2. Other liquids, like alcohol, are similar to water. (Similar Case)
  3. Therefore, they are may be made up of still more simple elements. (Provisional Inference)

Argument by analogy is most commonly used to form conjectures in mathematics and hypothesis in science. It is a very common form of argument in the human sciences and in courtrooms. It is especially handy in automotive repair and medical experiments (mice respond this way, therefore human beings may as well). A good example of religious and philosophical argument by analogy is The Analogy of Religion by Joseph Butler.

Therapeutic Dialectic

I mentioned earlier that dialectic has explicit uses for monologue, namely arguing with emotions, impulses, and impressions so that your intellect can aim your will toward what is good or healthy. Martha Nussbaum quotes Epicurus making this point:

Empty is that philosopher’s argument by which no human suffering is therapeutically treated. For just as there is no use in a medical art that does not cast out the sicknesses of bodies, so too there is no use in philosophy, unless it casts out the suffering of the soul (Therapy of Desire: Theory and Practice in Hellenistic Ethics, 13).

Argument/dialectic was considered to be the primary tool to be used in moral development across the philosophical school of the ancient world. Pierre Hadot saw dialectic and rhetoric as method of discussion and controlling your self-talk:

The means employed are the rhetorical and dialectical techniques of persuasion, the attempts at mastering one’s inner dialogue, and mental concentration. In all philosophical schools, the goal pursued in these exercises is self-realization and improve­ment. (Spiritual Exercises from Socrates to Foucalt, 102-103)

Logic/dialectic is a tool for pursuing moral and personal excellence. It allows you to see which impulses contradict your goals, which controlling thoughts are actually false, and which choices more appropriately set you on the path to goodness, truth, and beauty. 

Summarizing the Benefits of Learning Logic/Dialectic

  1. Logic trains us to have mental resilience.
  2. Learning logic trains us to find the truth in any discipline. It functions as the foundation of everything from jurisprudence and forensic science to chemistry and mathematics.
  3. Learning logic helps us to question authority. This is crucially important in our era, when truth is essentially equated with “what authorities say.”
  4. Logic enables temperance (the virtue of responding rightly to our passions/feelings).
  5. Learning logic can help you to discover small hypocrisies in your life wherein your actions do not match up with the apparent truths you accept.
  6. Learning logic can help you to deal with difficult people.
  7. Learning logic can help you become a more effective writer by helping you to avoid contradiction and to write paragraphs in a sequence which flows from premise to conclusion or from assumptions to application and so-on.

Resources for Learning Logic:

  1. Online Tools:
    1. Lander Logic Page
      Here you’ll find example and exercises to practice.
    2. Khan Academy
      There are free exercises and videos in the critical thinking section to which I’ve linked.
    3. Any number of old logic text books available at books.google.com for free.
  2. Books
    1. Socratic Logic by Peter Kreeft
    2. The Logic of Real Arguments by Alec Fischer
      I’ve used excerpts from this in my logic class. It mostly inspired me to have my students get out of logic textbooks and into actual arguments on subjects of human interest..


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