Deduction, Induction, Abduction, and the Problem of the True Premise
The intellectuals propose three basic forms of reasoning: inductive, deductive, and abductive. Without true premises, no reasoning is sound. In other words, if we make up stuff and inject that made-up stuff into our reasoning, we aren’t thinking rationally anymore. Our reasoning isn’t sound. Sound reasoning is sane reasoning. So, we need true premises to think in a rational way.
The trouble is that the human mind has no path to true premises. It does have the power to make up stuff and to use tricks (fallacies) to make the made-up stuff seem true, but it can’t reason to a true premise. It can live a brute beast life that merely reacts to the five natural senses. It can learn what works. It can learn what happens if we do a certain action, which is what real science is about. But it can’t reason about things like God, the age of the earth, the age of the universe, right, wrong, or truth without drifting into the land of make-believe.
Inductive reasoning (as opposed to deductive reasoning or abductive reasoning) is a method of reasoning in which the premises are viewed as supplying strong evidence for the truth of the conclusion. While the conclusion of a deductive argument is certain, the truth of the conclusion of an inductive argument may be probable, based upon the evidence given. ~ Wikipedia
Some dictionaries define “deduction” as reasoning from the general to specific and “induction” as reasoning from the specific to the general. While this usage is still sometimes found even in philosophical and mathematical contexts, for the most part, it is outdated. ~ Internet Encyclopedia of Philosophy
Deductive Reasoning: True premises use valid form to prove a conclusion. If the premises are true and the form is valid, the argument is sound, and the conclusion is true. If the premises aren’t known to be true, or the form is invalid, the argument is unsound, and the conclusion isn’t known to be true.
If X is true, then Y must be true. X is true. Therefore, Y is true.
Inductive Reasoning: True premises use language to argue for a conclusion. If the argument convinces someone, that person says that the argument is strong and cogent. If the premises aren’t proven, the inductive reasoning isn’t sound. If the premises are proven, but a person isn’t convinced, that person says the argument is weak and isn’t cogent. The word, “cogent,” means convincing or compelling, so inductive reasoning often speaks to persuasion rather than knowledge of the truth. However, inductive reasoning can also be helpful for developing pragmatic solutions. All godless science is based on inductive reasoning, and some of that science produces working solutions and products. The usefulness of inductive reasoning depends on the form of inductive reasoning as we’ll define below.
If X is true, then Y could be true. X is true. Therefore, Y could be true.
Inductive reasoning is fundamentally unreliable. Some say that it deals with percentages of probabilities, but that isn’t usually the case. Most of the time, the thinkers who claim that something is probable or improbable haven’t calculated anything. They go by gut feeling or simply make an unsupported assertion. They might even calculate a supposed probability using an actual formula, for instance, Bayes Theorem. But if they insert assumed numbers into the calculation, they nullify the value of the calculation. As we look at various forms of inductive reasoning, we realize that those forms aren’t all created equal.
All the people I have known prefer Fords. Therefore, all people prefer Fords.
Our historical records show that it rains the following day twenty percent of the time whenever we have the current atmospheric conditions. Therefore, we have a 20% chance of rain tomorrow.
Twenty-seven years ago, I was a Christian, and I prayed that God would answer my question about why He decided to send the Genesis Flood. Since I didn’t receive an answer that I couldn’t argue against, I conclude that God doesn’t exist.
Argument from Analogy:
Rats are similar in some ways to humans. We tested our drug on rats and haven’t seen any adverse effects. Therefore, it’s less likely that our drug will have adverse effects on humans.
Some people believe that natural selection caused some evolutionary changes. They believe that other factors caused other evolutionary changes. Therefore, molecules-to-humanity evolution happened.
Argument from Prediction:
If it’s raining outside, I would expect the sidewalk to be wet. The sidewalk is wet. Therefore, it’s raining outside.
Inductive reasoning can also be a Bayesian inference or inductive inference.
Thinkers reason with all of these inductive methods, and some of these methods are logical fallacies. Some of them can be helpful for decision-making, but none of them can lead to knowledge of truth. Most of them just give the illusion of rational thought but are irrational. To think irrationally is to think insanely.
While inductive reasoning can’t lead to knowledge of truth, we can use it to extend our observations and make predictions about the physical realm. The classic example is the ball on the table. We roll the ball off the table, and we observe that it falls to the ground. It never floats in the air. It never rises. If we do this multiple times, we can plan that the ball will fall the next time we roll it off the table. We can extrapolate that the ball will fall off the table every time if we do this same experiment once a minute for one year, ten years, or a thousand years. That’s inductive reasoning. It’s a form of inductive reasoning.
This principle works well for a ball on a table and its behavior when it hits the edge of the table. It doesn’t work at all for telling us why the ball always drops and never goes up. It doesn’t tell us whether there’s something about our observation that we don’t understand. Therefore, by this inductive inference, we can’t say for certain that the ball won’t float up the next time we knock it off the table. Inductive inference provides a way of survival, but it doesn’t lead us to knowledge of the truth.
By comparison, deductive reasoning is absolute but also requires a true premise. Only divine revelation can provide a true premise. By revelation we can know that God is faithful to enforce the laws of nature, so we can be confident that He’ll continue to enforce the law that makes the ball fall off the table. If He chooses to do a miracle (do something different), we know that He’ll make that slight and temporary exception in His wisdom and to complete His good purpose.
Since the premise for this knowledge is divine revelation and truth, we have a true premise, and we can use that true premise to reach a true conclusion. We can know with certainty. Therefore, we can continue to do science using inductive reasoning. We can continue to have absolute knowledge using deductive reasoning based on divine revelation. However, we would be irrational if we were to have absolute belief or conviction based on inductive reasoning.
Intellectuals argue against the problems they have with rational thought. When a person exalts the human mind and its ability to reason, the Münchausen trilemma (ungodly thinking problem) is an irritation that they must explain away. As we’ve seen, the ungodly thinking problem keeps human minds from having true premises without divine revelation.
Intellectuals have many ways to explain away this problem, and one of those ways is by appealing to induction. Typically, intellectuals will make an assertion that goes well beyond the information that they can get from their five senses. For instance, they may deny that anyone can know God. They may dogmatically believe in evolutionism or old-earthism. They may make statements about morals or history. They have no way to have a true premise for claims that go beyond their five senses, but they say, “I use inductive reasoning rather than deductive reasoning, so it doesn’t matter that I can’t prove my premises.” That isn’t true. Both inductive and deductive reasoning require true premises or they’re irrational. They aren’t sound. They aren’t sane.
Abductive Reasoning: In the absence of a true premise, both deductive and inductive reasoning default to abductive reasoning, which some people say is guessing. However, abduction isn’t always guessing. It’s intuitive. Abduction is a source of information in the same way that observation is a source of information. God can speak through the intuition, but so can demons, and so can our fallen fleshly minds. God tells the truth, demons lie, and the fleshly mind makes up stuff. We pray for God to make the difference plain to us, and He promises to answer that prayer.