Young Writers Society

We go about our everyday lives experiencing what we think to be ‘the world’. One way we can understand our experiences is that there is our mind, and then there is the world outside our mind. Mind, in this case includes things we can perceive with the five senses. It is the subject that does the experiencing. John Locke created an account of the mind and its relation to the external world in his Essay Concerning Human Understanding (henceforth to be called his Essay).

John Locke was a philosopher who lived in England during the 17th century. He initially studied at Christ Church, an Oxford college, after which he decided to pursue medicine. This led to his encounters with influential scientists and doctors. Today he is mainly known for his 1689 Essay. Notably, he was also involved in politics, [2] but we will be skipping over that part of his life in this article.

According to Locke, everything in our experience is an idea. We have ideas of the external world, which reside in our internal world or our mind. Locke provided a long list showing what could count as an idea. Included in his list in rapid succession are “elephant”, “army” and “drunkenness”, among other things. [1: Book 2-1-1]

Any idea we have of the external world is caused by something in the external world. We can call these things external world objects. External world objects interact with our sense organs. [1] How? Locke subscribed to mechanical philosophy, which is the theory that the behaviour of physical objects can be explained by their motion and impacts onto one another. [2] Say if an egg rolls down a hill after someone touches it, a mechanical philosopher would explain that as: the motion of the person’s finger impacted the egg and caused it to roll down the hill.

To understand how this is relevant, we also need to consider corpuscular theory, a scientific theory from that time period that Locke subscribed to. This theory was hatched by Robert Boyle, whom you will probably recognise as the namesake of Boyle’s Law. According to corpuscular theory, any bit of matter in the universe is made out of particles. Different people had different opinions on whether these particles could be further divided or if vacuums existed. [2] The upshot of this for our purposes is simply that Locke believed motion could be transferred from an external world object to our sense organs by means of corpuscles. This explains why we can receive an idea of an egg’s shape without our eyes being pressed up against it.

However, the ideas that we receive from these interactions are simple ideas. For example, the cream colour of an egg, its roundness, its smoothness is each considered a separate simple idea. Kind of like a chemist, with elements and compounds, Locke divided his world into simple ideas and complex ideas. Simple ideas could be compounded into complex ideas. To acquire an idea of an egg, we would compound all the aforementioned simple ideas to create a complex idea. [1]

This part of Locke’s account opens some potential holes regarding how accurate our perception of the external world can be. Locke holds that some of our ideas of external world objects truly resemble them, while others do not. He said the resemblant ideas were ideas of primary qualities, while the rest were called secondary qualities. [1]

To make sense of this, let us recall our cream-coloured egg. For Locke, the space that the egg takes up is a primary quality. In the external world, the egg takes up as much space as we can see with our eyes or feel with our hands. As such, our idea of the space an egg takes up resembles the space it actually takes up in the external world.

In contrast, the cream colour is a secondary quality. The way we perceive the egg’s colour (to put it poetically: a colour that reminds us of bare skin, which looks ‘natural’ and perhaps is soothing) is not how the egg truly looks in the external world. There is nothing resembling ‘cream-colour’ in the external world. There are only corpuscles that have qualities such as space, motion and shape.

What makes up a secondary quality then? Locke would say it is a particular arrangement of corpuscles. [1] An arrangement like this causes us to have an idea of an egg being a cream-coloured object. However, if we could somehow find out about what the ‘real egg’ looks like without the interference of our eyeballs, Locke thinks we would not see anything like our perception of ‘cream-colour’.

One of the problems with Locke’s account is as follows. All our ideas come to us via our sense organs, and our experience of the external world is only ideas. We never come to know what external world objects are like except through our senses. So, can we really know whether ideas resemble or do not resemble external world objects?

Think about times when what we perceive turns out to be an illusion. When we look at a straw in a glass of water, it looks as though the straw is cut in two because of the refraction of light. This is not usually a problem for us because we can use another sense, like touch, to confirm that yes, that straw is still whole. However, Locke’s account seems to allow that all our senses are feeding us illusions constantly about particular things, namely the secondary qualities. There also is no way for us to know that they are not also giving a misrepresentation of primary qualities.

Ultimately, Locke says an egg is not really the way we perceive it in our experience. Beyond what our mind perceives, there is an objective external world, wherein the ‘real egg’ exists. His distinction between primary and secondary qualities allows him to hold both of these views. The ‘real egg’ shares some traits with our idea of an egg, but not others. Something to ponder about this is whether we can know if the ‘real egg’ shares any traits with our perceptions of an egg at all, given that we cannot directly grasp the ‘real egg’.

References

[1] Locke, John. (2004, January 1). An Essay Concerning Humane Understanding, Volume 1. Project Gutenberg. https://www.gutenberg.org/ebooks/10615

[2] Uzgalis, William. (2020). "John Locke". In The Stanford Encyclopedia of Philosophy (Spring 2020 Edition). Edward N. Zalta (ed.). https://plato.stanford.edu/archives/spr2020/entries/locke/