Empiricism is the view that all knowledge comes from experience whatever is the mind got there through the senses. Locke was an empiricist who held that the mind was tabula rasa or a blank slate at birth to be written upon by sensory experience. Empiricism is opposed to rationalism or the view that mental ideas and knowledge exist in the mind prior to experience that there are abstract or innate ideas.
George Berkeley argued against rationalism and materialism. He also criticized Locke on many points. He said most philosophers make an assumption that has no proof of the existence of matter. Berkley questioned the inference that material things cause our sensory experience or that our sensory experience is material things. Berkeley originally wondered if we as humans actually experience an object as it really was, or was what we physically saw. The materialist feels that the information received through sense experience gives a representative picture of the outside world and one cannot penetrate to the true essence of an object... Although the idea is logical, it does contain certain grounding for agnosticism. John Locke claimed that primary qualities are those that exist within the body of an object and outside of our perception. He believed they are inseparable from body and his list consisted of motion, bulk, figure, number, and texture. Primary qualities are those qualities, which are present in the object itself, such as extension. Secondary qualities are only present in the viewer, such as color. In a world in which there are no animals with color vision, there are still objects that reflect lights of various wavelengths, but there is no being that would interpret those waves as "color.
He supported his definition of primary qualities by claiming that if an object were continuously divided, the primary qualities would remain the same. However, he suggested that secondary qualities were only powers that the object has to cause us to