Post Author: Bill Pratt
Philosophers who study how we know things (epistemologists) have long debated whether we have innate or intuitive knowledge. This kind of knowledge is often referred to as a priori knowledge. It is knowledge that one has prior to or independently of sense experience. It cannot be proven by experience.
The debate over a priori knowledge is important to Christians because atheists, agnostics, and naturalists often deny the existence of most kinds of a priori knowledge and claim that we can only know what we observe with our senses. For example, do we know that raping little children for fun is wrong? Most people would say “yes” and in a poll I ran last week on the blog, 89% did answer “yes.” Now, this is hardly a scientific poll, but the results, I think, are still indicative.
This is an example of a priori knowledge, because we don’t come to this conclusion by observing the world around us – we just know intuitively that raping little children for fun is wrong. Philosopher Louis Pojman lists eleven examples of propositions that have been proposed as a priori knowledge by epistemologists:
- If John is taller than Mary and Tom is taller than John, Tom is taller than Mary.
- 5 + 7 = 12
- Nothing is both red and green.
- Some sentences are not both true and false.
- If Socrates is a man and all men are mortal, Socrates is mortal.
- Every event has a cause.
- All bodies are extended.
- A greatest possible being necessarily exists.
- It is wrong to harm people just for the fun of it.
- If I believe I exist, I exist.
- Not both p and not-p.
These propositions represent several different categories of knowledge: mathematics, knowledge of “greater than,” laws of logic, morality, deductive logic, causality, knowledge of space, knowledge of God, and introspective knowledge.
Philosopher Alvin Plantinga holds that a priori knowledge, besides being true, must fulfill four conditions:
- The proposition p must be believed and believed to be necessarily true.
- You must be able to form the belief immediately upon understanding it.
- The proposition p must not be believed on the basis of perception, memory, or testimony.
- The belief must be accompanied with a certain phenomenal feel, what the rationalists call intuition.
What do you think? Do you think certain kinds of knowledge are built in to human beings, that we just know some things intuitively? If so, what kinds of things do you think we know intuitively?
I’ve given you 11 examples of what some philosophers have considered to be a priori knowledge, but I’d like for you to vote in the poll below. The assignment is easy: tell us which of the 11 propositions, once you’ve read and understood the terms in them, are intuitively obvious or self-evident. I look forward to seeing the results.