Rationalist philosophers have argued that reason is primarily responsible for knowledge. Because of this, such philosophers have tried to find a way in which to explain how rational knowledge is more fundamental than experience. To do this they have relied upon two central concepts: innate ideas and a priori knowledge.

1) Innate Ideas. When we are born, so the Rationalists argue, we already have a store of ideas that we draw upon in order to help make sense of the world. These ideas are called "innate", meaning "in born". Examples of such ideas are mathematical truths (2 + 2 = 4), truths about God (that He exists, is good, all powerful, etc.), the concept of time, the notion of causality and other logically and metaphysically necessary principles.

2) A Priori Knowledge. The term comes from the Latin phrase meaning "before" or "prior to" and is used to refer to ideas that appear to be true before - or regardless of - experience. Innate ideas can also be a priori, depending on whether the idea can be said to always have existed.

Exercise

Given the above definitions, which of the following statements would you say are a priori.

Statement	A priori
I have a body
27 + 25 = 52
Internal angles of a triangle add up to 180 degrees
There is a God
There is no God
What goes up must come down
Causes have effects
Time is linear
Every cloud has a silver lining
I am a thinking thing

Click here to view my answers.

Notice that - according to my answers - only two of the statements are genuine a priori ones. This is because all the other statements rely in some way on experience. Some attempts have been made to argue that some things - such as the existence of God, cause and effect relationships, etc. - are a priori. These are examples of metaphysical necessity referred to earlier.

Problems with this View

The Greek philosopher Plato was one of the first to propose that certain types of knowledge are innate. His idea was based mostly on the concept of remembering, which brings us to the first objection to innate ideas:

1. How is it possible to distinguish "remembering" from "learning"? If we can't, doesn't that make the idea redundant?

Other objections are:

2. Most ideas seem to rely in some way on the real world to bring them out. For instance, how could it be said that a young child knows that "all the internal angles of a triangle add up to 180 degrees", when it may not even know the name for the shape?

3. If mathematical ideas were innate, wouldn't we already know the answers to complicated sums? And yet, most of us have difficulty adding up relatively simple 4-figure sums (such as 1425 + 3548).

4. If ideas such as "God exists" are innate, why doesn't everyone believe that?