Epistemology Day 04, 1 Epistemology Day 4: “Rationalism to


Epistemology Day 4: “Rationalism to Empiricism”


1. Empiricism v. Rationalism (20 mins)

2. Dialogic Notebook—which do you believe?

(30 mins)


1. Lecture

2. Student exercise

Assignment for this class:

Stanford Encyclopedia of Philosophy

, “Rationalism v. Empiricism,”

Section 1

Instructor’s Introduction:

Descartes is the “poster boy” of rationalism. Before moving on to the empiricists, it will be helpful to students to understand the differences in these perspectives.

The really tricky bit here tends to be getting students to be able to differentiate

a priori


a posteriori

knowledge. They frequently get hung up on the idea that they learned what a triangle is by someone showing it to them—so it seems like they learned it through sense experience.

But what makes a triangle, a triangle (e.g., three sides, angles adding to 180, etc.) is based in the concept of a triangle, not in our experience of them.

Goals and Key Concepts:

1. Students should be able to differentiate between rationalism and empiricism and understand the major points of disagreement between the two.

2. Students should be able to articulate which they find more compelling and why.

3. Key concepts: a priori, a posteriori, analytic, synthetic, rational, empirical

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1. Empiricism vs. Rationalism


Rationalists: Stress role of reason in knowledge, play down role of sense experience. For rationalists (like Descartes), the source of knowledge is innate ideas—either knowledge we’re born with or

a priori

concepts that are presumed by all knowledge.

Empiricists: Stress role of sense experience in knowledge, play down role of reason. For empiricists, all ideas come from experience—either directly, or by abstracting from experience.

A Priori

Knowledge: (conceptual truths)

A priori

claims do not rely on sense evidence for their truth. That is, their truth value does not depend on facts in the world. e.g.:

“all triangles have 3 sides” 

You don’t know this from comparing actual triangles–you know by analyzing what the words mean.

“A vixen is a female fox”

this would be true even if no foxes existed, because that’s just what ‘vixen’ means.

“2+2=4” 

again, a conceptual truth.

A posteriori

Knowledge: (empirical truths) These rely on sense evidence for their truth. That is, we have to check on states of the world to know whether they are true. e.g.:

“there is a table in this room”

we have to look around the room to see whether this is true.

“I’m wearing shoes” 

we have to look at my feet to confirm.

IDEALIZED RATIONALISM—“Idealized” because it’s mostly true, but there may be rationalists who don’t agree with each part of this.


There are fundamental, informative truths known a priori

(intuitive form): Through reason (and not based on sense experience, i.e., a priori), we can know certain fundamental, informative truths about the world.

This is not just telling us things that are true by definition, e.g. “A bachelor is an unmarried

(adult) male,” or “a triangle has three sides.” Rationalists argue that truths such as “everything has a cause” are both

a priori

(knowable independent of experience) and tell us real facts about the world.

2. Stress logical/mathematical reason as a model for knowledge. This is definitely what we saw with Descartes—his method was very much like what you find in geometry. Start with something that has to be true (e.g. axioms, theorems) and then base the rest of your knowledge on that.

3. Play down natural sciences as based on sense observation. It’s NOT that they don’t find science interesting or useful (Descartes was a scientist), but they think all knowledge that comes

726926926, 3 from our senses is “suspect,” and we can be wrong about it in a way that we can’t be wrong about rational knowledge.

[So, for rationalists, math/logic provide “real” knowledge, science is only “okay” knowledge.]

4. There are innate ideas. That is, we have knowledge that we’re born with (generally, these will be the truths in #1 above).

IDEALIZED EMPIRICISM—Same deal, not every empiricists will agree with all of this, but it gives a nice general picture.

1. Deny that truths are

a priori

. All informative truths are known

a posteriori


2. Deemphasize the role of logical/mathematical reasoning. They think it is VERY important

(they know you can’t do science without it, but they think it isn’t as important as learning facts about the world), but doesn’t itself lead to truths about the world.

3. Stress the role of natural sciences as based on sense observation. The kind of knowledge we’re


interested in tells us about the world—and that’s what science gives us.

[For empiricists, science is “real” knowledge. Logical and math are useful and important, but not as important as science in helping us discover truths about the world.]

4. There are NO innate ideas. Every idea we have, we gained through experience.

We can’t know informative truths (that is, truths about the world) through reason. We know informative truths only on the basis of sense experience, that is,

a posteriori.





a priori

R: yes E: no

R: yes E: yes

a posteriori

R: yes E: yes

R: no E: no

Notice—the only place they disagree is over whether there is synthetic

a priori


Keep this in mind as we get ready to start the epistemology section.

2. Dialogic Notebook Exercise

See Appendix for a full description of the exercise.

Round 1: Student should briefly describe what


thinks knowledge is. (This can either be a rehash of what they wrote on Day 1, or they may have changed their minds).

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Round 2: Read then analyze—do you think this view seems more like a rationalist or empiricist view? What evidence supports your claim?

Round 3: Read ONLY the original statement then analyze—do you think this view seems more like a rationalist or empiricist view? What evidence supports your claim?

Round 4: Read the responses. Do you agree? What would you add to strengthen your view?

Small group discussion: Can you agree on rationalism or empiricism?

If so, what do you think is the best reason to pick that view? If not, what is the biggest thing you disagree over?