In previous posts, I’ve attempted to show that argumentation (as distinguished from bickering or fighting) is a good thing – the process in which we take observations and evidence and draw the-great-detective-1425530-1920x1440conclusions about the world around us. We saw the first principles of logic that form the foundation of reason, and that true, biblical faith is based on reason, rather than being opposed to it, as some misunderstand. Building on this, let’s now look at the most common types of arguments: deductive, inductive, or abductive.

Argument Types

In a deductive argument, the premises lead to a conclusion which, if the premises are shown to be true, follows irresistibly. So, for a famous example:

  1. All men are mortal. (premise 1)
  2. Socrates is a man. (premise 2)
  3. Therefore, Socrates is mortal. (conclusion)

Intuitively, this should make sense. The conclusion follows from the premises, if they are accepted as true. This is the strongest form of argument.

Inductive arguments contain a conclusion that is established by the strength of their premises, and so rather than the conclusion irresistibly following the premises, it is only probable, not certain. Take this example:

  1. It has rained every day for the last thirty days in Birmingham. (premise)
  2. Therefore, it will probably rain today in Birmingham. (conclusion)

Is the conclusion certain? By no means, but probability seems to be in favor of its being true.

Abductive arguments, sometimes known as inference to the best explanation, draws a conclusion taking into account multiple pieces of data and attempts to most comprehensively explain them all. This is the form of argument frequently used by criminal detectives (such as Sherlock Holmes). Here’s an example:

Let’s say I am in a room with no windows in the interior of a building.

  1. Someone walks in the room with wet shoes and a dripping umbrella. (data 1)
  2. I’ve been hearing some ominous booming and rain-on-roof sounds. (data 2)
  3. The weather app on my phone says there are thunderstorms in my area. (data 3)
  4. A reasonable conclusion would be that it is raining outside currently. (conclusion)

An interpretation of the data occurs which lead to possible explanations which are compared with one another. The chosen conclusion is not certain, but it seems more likely than alternate explanations that may be offered.

Argumentation Gives Knowledge

So to sum up, concerning arguments, two or more premises (including hidden premises) are put together to lead to a conclusion.  The premises must each be evaluated for probability of truth in order to determine the strength of the conclusion.  Since in most cases the premises are assigned probability less than 100% certainty, it usually leads to conclusions which are themselves less than 100% certain.  However, this is simply the way we operate in life.  In many instances, we consider ourselves to have knowledge on topics for which we have varying degrees of certainty.  Different subjects require differing levels of certainty to claim knowledge, yet we navigate reality, personally and corporately making important decisions on what we consider to be (un)acceptable levels of certainty.  For example, criminals are executed through a decision of guilt rendered beyond reasonable doubt, not beyond all doubt.  If we are justified at this level of moral certitude to impose a death penalty on another, surely, then, absolute certainty is not required to claim knowledge.  Through diligence and clear thinking, we work to make livable decisions for life, morality, and religion. Through proper exercise of deduction and induction, we are able to approach truth.

Having established (I hope!) the existence and knowability of objective truth, and the value of good argumentation to apprehend truths, I will hereafter shift gears from the mechanisms of knowing truth to the arguments themselves that have been particularly convincing in my mind, as well as many others, for the truth of Christian theism and worldview. I hope you’ll join me!

Comments, questions, challenges? Email me through the form on my “about” page, we’ll discuss, and your comments may inspire a follow-up post!