3.3 John Locke and the Blank Slate

As an empiricist, Locke rejected the idea made popular by rationalists that humans are born with innate knowledge or ideas. Instead, Locke argued that when we are born, our minds are like a tabula rasa: a blank slate with nothing written on it, and that all of our knowledge comes from experience. In other words, the mind starts completely empty and gains knowledge as it interacts with the world.

Locke believed that knowledge is built step by step through experiences and reasoning.

1. Sensations: These are the first inputs to the blank slate. For example, seeing the color blue or hearing a musical note. This is the raw information that we receive from our senses, such as sight and sound. Sensory experiences provide raw data from the external world.
2. Reflections: These are the second inputs to the blank slate. Once we have a sensory experience, our mind processes them. Reflection involves thinking about these sensations, comparing them, and making judgments. In that way, our mind processes, analyses, and organises the sensory information that it receives.

Sensations give us the content, and reflections give us the understanding. Together, the two processes shape how we build complex ideas such as justice.

Through reflection, we realise that some qualities (primary) are objective, while others (secondary) are subjective. For instance, by comparing experiences, we understand that shape and size exist regardless of perception, but color and taste change depending on the observer.

Locke made a distinction between primary and secondary qualities to explain how we perceive and understand the world:

• Primary qualities: According to Locke, these are properties that objects have regardless of who observes them, such as shape, size, and motion, and they are measurable. They exist independently of our perception and are part of objective reality. This means these properties would exist even if nobody perceived them.
• Secondary qualities: These are properties that depend on the observer’s subjective perception, such as colour, taste, and sound. For example, the blueness or sweetness of a blueberry does not exist in the blueberry itself; it exists in the mind of the person who is perceiving it.

This distinction proposes that some aspects of reality are objective (based on facts and evidence), while others are subjective (based on personal feelings or opinions).

Through reflection, we can realise that some qualities are objective (primary qualities), while others are subjective (secondary qualities). For example, we understand that shape and size exist regardless of perception, but color and taste change depending on the observer.