John Locke: Part One Enlightenment (1632–1704)



Book I

An Inquiry into the understanding, pleasant and useful. Since it is the understanding that sets man above the rest of sensible beings, and gives him all the advantage and dominion which he has over them; it is certainly a subject, even for its nobleness, worth our labour to inquire into. The understanding, like the eye, whilst it makes us see and perceive all other things, takes no notice of itself; and it requires art and pains to set it at a distance and make it its own object. But whatever be the difficulties that lie in the way of this inquiry; whatever it be that keeps us so much in the dark to ourselves; sure I am that all the light we can let in upon our minds, all the acquaintance we can make with our own understandings, will not only be very pleasant, but bring us great advantage, in directing our thoughts in the search of other things.

A recent article in the Harvard Business Review examined the importance of metacognition, or “thinking about thinking.”  Broadly speaking, metacognition is about being more inspective about how you know what you know. It’s a matter of asking ourselves questions like: ‘Do I really get this idea?’

John Mark Reynolds said this in his book, The Great Books Reader:

Many Americans fear that philosophy will make them useless. They will start thinking about ideas, and soon that will lead to thinking about thinking.

They’re right that the topic will quickly arise, but they shouldn’t fear it. John Locke, the intellectual founder of most of the world’s democracies, thought it necessary that free men and women should think about thinking. In fact, he believed bad thinking about thinking would undermine society.

John Locke lived in an age when every educated person was expected to have a coherent philosophy. This sensible expectation included having a view about what was “knowable” and how it could be “known.” Questions about knowledge were part of the philosophical discipline called epistemology, and Locke’s generation believed any person worthy of voting should have thought out how to make good decisions about that vote.

Can you examine your thoughts objectively?

Join the discussion on Facebook HERE 


John 1:1

In the beginning was the Word, and the Word was with God, and the Word was God.

John Mark Reynolds is the president of The Saint Constantine School, a school that aspires to preschool through college education. He is also a philosopher, administrator, and joyous curmudgeon. Reynolds was the founder and first director of the Torrey Honors Institute at Biola University. He was provost at Houston Baptist University where he was instrumental in starting the graduate Apologetics program and a cinema and new media arts major. John Mark blogs at Eidos on the Patheos Evangelical platform and has written for First Things and the Washington Post. He is an owner of the Green Bay Packers.


D I G  D E E P E R

On Certainty

Janelle Klapausak

John Locke’s Essay Concerning Human Understanding begins with the stated project to “search out the bounds between opinion and knowledge.” Like most early modern philosophers (writing from c. 1600–1800), Locke was fascinated by the question of certainty. He wanted to know what, of all we take for granted, is truly certain (knowledge) and what is merely opinion. This question was a natural one for Locke and his contemporaries to be asking after decades of profound change for Western Europe.

During the sixteenth century, two overhauls of thought had permeated the Continent. The first was the Protestant Reformation, which “began” with Luther’s posting of his Ninety-Five Theses in 1517, and the second was the Scientific Revolution, which most scholars date to the publication of Copernicus’s On the Revolutions of the Celestial Spheres in 1543.

These two intellectual movements, different as they might have been in other ways, shared one crucial characteristic: both cast doubt on propositions that had been accepted for centuries. The Reformation called into question Roman ecclesial authority; the Revolution cast doubt on the authority of Aristotle’s method of scientific inquiry.

The philosophers reacting to these revolutions in the early seventeenth century felt the foundations of knowledge shifting under their feet. Their understandable response was to try to find a way to sort through the list of things we all think we know and figure out which are true and which are false. They wanted to reestablish a solid foundation for knowledge by developing a method to discern that which is certainly true.


John Locke’s first move in addressing this question was to reject the theory of innate ideas. In the preceding centuries, most philosophers had believed there are certain propositions with which we’re “preprogrammed.” These might include logical and mathematical concepts (like the idea that a proposition cannot be both true and false at the same time) but might also include ethical propositions (e.g., that murder is always wrong). Locke rejects this doctrine that certain beliefs come “preprogrammed” in all people. Instead, he argues that the mind is a blank slate, or tabula rasa, at birth, and that every belief we have we get from observing the world around us.

This point is especially interesting because in René Descartes’s Meditations, published forty years before Locke’s Essay, he’d argued that our idea of God is one of these innate ideas, and that it is through this notion that we can be certain that God exists. Descartes believed that only God could cause this idea of God to exist in our minds; Locke maintained that we can get our concept of God from observing the world around us, whether or not God exists.

In a second important shift, Locke insisted that all knowledge comes from observing the world, but it’s not the case that all the things we observe are actually in the world. Locke said the qualities we observe in the world can be split into two categories. Some qualities—like an object’s solidity or its shape—are qualities in the object itself, what Locke calls primary qualities. However, in Locke’s argument, sometimes when we’re observing a quality of an object, what’s actually happening is that the object is affecting us in some way. This is why, he said, the same water can feel hot on cold hands and cold on hot hands: the hotness or coldness isn’t a quality the water itself has, but, instead, it’s a power that the water has to affect us. It’s not that an object is yellow, but, rather, that an object produces a yellow effect on us when we observe it.


The practical effect of these two propositions, taken together, is to create a gap between how we experience the world and how the world really is. The rejection of innate ideas means that our observations are the only way we can get knowledge about the world, and the distinction between primary and secondary qualities means our senses don’t give us information about the world as it is. Instead, objects in the world cause us to have impressions, which may or may not be related to how those things actually are.

Locke deduced that the list of “things we can be sure about” is much shorter than we may have thought. The world presents us with impressions, and we have no way of getting at the world itself to discover whether or not the impressions are true.

This itself was a common story among early modern philosophers. The search for certainty did not lead to sure knowledge, as thinkers like Descartes hoped it would. Instead, it led to increasing skepticism about our ability to know anything for certain.

This may seem like a depressing conclusion, but it isn’t one at which Christians should be too surprised. The “early modern project” was to ground certainty in human reason. If this project fails, it may be simply because human knowledge depends on something else for its certainty.
Discovering that we cannot trust in our reason alone, but, crucially, must trust that God has made our reason and our perceptions accurate, may be a substantial and necessary correction in our view both of ourselves and of our relationship to God—a correction we can thank Locke for revealing.

Janelle Klapausak is an assistant professor at Biola University’s Torrey Honors Institute and is currently a doctoral candidate at Baylor University.

John Mark Reynolds, The Great Books Reader: Excerpts and Essays on the Most Influential Books in Western Civilization (Grand Rapids, MI: Bethany House, 2011).