Rationalists vs. Empiricists

By the 19^th century, western philosophy had fallen into two camps, whose opposing views centre on the question of how we can gain knowledge. The first were the ‘Rationalists’, who believe that some knowledge is knowable by intuition only (independent of sense perception), and that further knowledge can be deduced from this initial knowledge by logical argument, i.e. reasoning. Rationalists also believe there is knowledge that we know innately. This is most clearly seen in nature, where animals appear to know how to do some things instinctively. Rationalists tend to believe that there is some knowledge that can’t be gained through experience, and that knowledge gained through reason is superior to knowledge gained through experience (e.g. more certain). The most extreme Rationalists believe that all knowledge comes from reason. Empiricists on the other hand, believe that all knowledge comes originally from sense experience. This is the basis for modern scientific method, where conclusions are drawn from a mass of observations and data. Empiricists are more inclined to be sceptical. They generally accept that some knowledge cannot be gained by experience, but conclude therefore that there are some things which we cannot know. Russell makes the point that Rationalists are inclined to generate large edifices of knowledge from a single starting point, forming an upturned pyramid. Such edifices are inherently unstable, as they are wholly reliant on the validity of the starting point and the initial reasoning. Empiricists start with a large and therefore stable base of experiences, but like a pyramid taper away to relatively little new knowledge at the top. Empiricists generally find experiences that are contradictory, so tend to reach more limited and general conclusions. The Rationalists at this point have included the likes of Descartes, Spinoza and Leibniz (and broadly speaking all philosophers before them). Empiricism, introduced by Locke, would be taken up by Berkeley and Hume, and taken in a more sceptical direction.

Subjective Reality

George Berkeley is most famous for his belief that matter only exists when it is perceived. Russell felt that Berkeley put forward sound arguments not for the fact that all reality is in the mind (as Berkeley intended to argue), but for the fact that we perceive qualities of things rather than things themselves, and that these qualities are relative to the percipient. Consider sight as an example. We can see the colour of an object, but what contacts our eyes is light, rather than the object itself that caused the light to be of a certain colour. The appearance of an object can also change depending on circumstances. For example, a sea might appear a beautiful deep blue from a distance, but have a different colour when swimming in it. An object could also have completely different colours when observed under a microscope compared to when it is observed normally. This raises the question, how do we know that other people perceive colours in the same way that we do? Maybe the world looks completely different to other people.

Similar points can be made about other senses, such as feeling hot or cold. If I have one hand in cold water and another in hot and I put both in medium water, the same water will feel both hot and cold at the same time. The sensations of hot and cold cause discomfort or even pain, which is in the mind, and our sensations are influenced by our minds as well as the object. Feelings of pain (caused by the perception of hot and cold) are the result of the temperature of an object, but are not part of the object itself. We cannot objectively feel the temperature of an object (e.g. in degrees Celsius). That might require, for example, feeling the amount of vibration of each particle so that we could determine the amount of heat energy, but our ability to feel objects does not work like that. There are some things Berkeley says that we can learn about objects. If we see a very small car we might reasonably deduce from our experience that the car is further away from us, but we cannot determine distance purely from seeing. If a person were suddenly able to see for the first time they would not at first be able to determine distance. Berkeley’s ideas are disorientating – how do we know objectively what anything looks, feels, sounds, or smells like? Berkeley believed that we cannot know anything about the world around us, and that all we have are ideas in our minds of what things might be like.

Constructing Objects in the Mind

Russell accepts the argument that we perceive ‘qualities’ and not material things directly as valid. He does however challenge the idea that the qualities we perceive are ‘mental’, i.e. they only exist in the mind. Russell argued that there are things that exist which no one has perceived or conceived (i.e. seen or thought of). For example, mathematical logic tells us that there are infinite amounts of numbers which exist, and it is impossible for all numbers to have been thought of. In addition, we use words to refer to groups of objects without having conceived of each object that the word could apply to. For example, the concept of a ‘pebble’ can apply to lots of objects all of which are unique. If we look across a pebble beach it is clear that not all of the pebbles have been perceived or conceived, yet they still exist.

Berkeley’s point only stands if we say that words only apply to objects that are observed. For example, if we say the word pebble can only apply to pebbles which have been observed. The argument for doing so is that any ‘object’ or ‘thing’ is really a collection of properties that we can perceive. To refer to something as an individual object is merely a useful simplification. It then follows that if no one is perceiving the properties of an object then it does not exist as a single object. It is as if the mind processes various perceived properties and generates ideas of the world around us, and each mind generates slightly different ideas of the world. Without the mind the world is a collection of sights, sounds, smells etc, but not discrete objects, until the mind collates properties together. This is my interpretation of what Berkeley is saying, and it could be countered that this overstates the extent to which the mind unites individual properties. The reason that we all largely agree on how properties should be grouped together as objects (we all agree that a plate is a different object to a table) is that their properties are easily distinguishable.