Philosophers such as Rene Descartes have imagined ideas and scenarios in their heads regarding philosophy that have required something additional in order to be explainable. Often, philosophers will use an example to guide others through the idea. The example is usually a hypothetical, but sometimes an example will be demonstrated to ensure maximum impact. Descartes uses the "Wax Example" in the second meditation of Meditations on First Philosophy to explain why we as thinking things are able to know a thing even if it has been altered or changed in some way.
To begin, it is essential that Descartes' wax example be explained. Descartes examines a piece of wax, noting its properties. It looks, feels, and smells like wax. Descartes then holds the piece of hardened wax next to a flame and the wax melts. He observes the wax again after it has melted and notes that it smells, looks, and feels different than it just did, but it is still obviously wax. Even though the properties of the piece of wax had changed, we are able to conclude that an object is still an object even if it has gone through change. We rely on our senses to provide us with the information that allows us to determine what a thing is, and although our senses tell us different things, our minds are able to take that information and determine what a thing is. Therefore, there must be something inherently characteristic of that thing; otherwise we wouldn't be able to conclude what exactly it was because our senses can deceive us.
Our senses are limited in that they strictly give us information about things; they do not interpret that information for us. We have to appeal to the mind every time we experience sensible objects. We constantly go to the mind to determine what the inherent quality of the thing is that makes it that thing. It is something that we cannot sense. There are two types of substances in our world; thinking substances and extended substances. Thinking substances are things in the mind and they do not physically exist. Extended substances are also known as material substances, and they are physical in their existence. The reasons that extended substances are called such is because the essential thing about those material objects is that they take up room and have mass, therefore extending in space.
The qualities of substances are also important when it comes to determining what exactly a thing is. There are two types of qualities; primary and secondary. Primary qualities do not depend on the way one experiences an object. An object that has mass is always going to have mass, and your senses are not involved. A secondary quality does depend on the way one experiences an object. The information that your five senses detect will affect the way you see the qualities. A secondary quality could be how an object looks/smells/tastes/sounds/feels to you. Our conception of secondary qualities can sometimes be misled if we have misinterpreted a thing's primary qualities. If, for example, one was to take a hallucinogen and then observe a tree, one would still clearly see that the tree is made of matter and takes up space, but one might not see the tree as brown with green leaves, but rather as some sort of swirl of colors that is not a real representation of the object. The former is a primary quality and does not change even if we are experiencing it in an altered way, but the latter is a secondary and can change. The wax in question undergoes a change in all of its sensible properties, and even though all of its secondary qualities are telling our senses that it is no longer that piece of wax, our minds are able to determine through the primary qualities that it is still indeed a piece of wax.
In this meditation, Descartes says, "I do not grasp what this wax is through the imagination; rather, I perceive it through the mind alone." In saying this, Descartes is showing that it is our minds that are truly recognizing things such as the piece of wax. There are certain qualities and traits of objects that we link to them in order to classify them. What those traits are, are separate from the object itself; they are abstract and intangible. The platonic essence of an object is what our minds use to identify an object, not our imagination's use of our senses' perceptions. Descartes is not actively feeling, smelling, and seeing the wax to determine that it is wax, but rather his mind is recognizing the platonic essence of the wax, identifying it even if it changes physically.
Descartes' second meditation is about more than just the wax example, but it is an important thing to be aware of, as it provides further evidence for his thoughts. Descartes says that he is a "thinking thing". He determined that is something thinks, it exists- I think which means that I must exist. This holds true, because even if you were to say "I talk, therefore I exist" that could be your senses deceiving you; with "I think, therefore I exist", thinking this is itself a thought, so there can never be any doubt as to whether or not I am a thinking thing. Descartes is showing us that there is a difference between minds and bodies, and that we know our own minds much better than we know any body, even our own.
Through the use of the wax example, Descartes is able to explain the differences between thinking and extended substances, primary and secondary qualities, and that we have greater knowledge of minds than we do of bodies. Descartes' second meditation relies on the discussion of the wax example to explain the significance of changes and how our senses and our minds can tell us two different things. In the end, it is our mind that is able to truly see the platonic essence of a thing and be able to identify it. Our senses have the ability to deceive us, making our minds the most reliable. Descartes has provided an explanation and example of his ideas, allowing us to see for ourselves what the mind and senses are capable of.