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The British Empiricists: Locke, Berkeley & Hume
While rationalism, the doctrine that knowledge is derived from the ideas of the mind, flourished on the European Continent from Descartes to Kant and Hegel, the British Isles produced their own brand of philosophy, known as empiricism, which comes from the Greek word for experience, empeiria. Empiricism is the doctrine that our ideas are derived from the experience of the senses. This is not to be equated with materialism. In this talk, I shall take the three chief British empiricists together: John Locke, George Berkeley and David Hume.
John Locke, who lived from 1632 – 1704, was an Englishman, associated with Christ Church, Oxford, and a Fellow of the Royal Society. The starting-point of his philosophy was his antagonism to Descartes. As he rightly remarked, thinking is not the essence of a human being (so I am not a thinking substance) but an activity or operation of the soul. Locke also reacted to Descartes who, like Plato, thought we have innate ideas. No, Locke said, we are not born with ideas but the mind begins like an empty room and we have to furnish it with ideas, which are like the furniture of the mind. Locke thought that there were two sources of ideas. One was sensation (the experience of the senses); the other was the mind’s reflection on its own workings; for example: understanding, comparing, negating, commanding, willing, doubting, fearing, etc..
Crucial to empiricism was its broad conception of ideas, which was made to include sensations and mental images, because the empiricists, like the nominalist William Ockham, did not admit that our general concepts were of anything in reality. Perhaps the fundamental point of Locke’s philosophy was that the immediate objects of our perception are ideas. In Locke, ideas come into the mind through the senses. For the ancients and medievals, ideas belonged strictly to the mind and were quite distinct from sensation. The consequence of holding that what we directly known is our sensations of things is that we have no direct knowledge of real objects in the world, as a realist holds. How then do we know that real objects exist? Locke could only say that we suppose that they exist as the cause of our sensations. For Locke all that I know is the qualities of things, not substances, which he said were “I know not what”.
Locke was followed by George Berkeley, who was the Protestant Bishop of Cloyne. He was born in the same year as Johann Sebastian Bach, in 1685, and died in 1753 (three years after Bach). On seeing that Locke held we do not know substances, Berkeley deleted substances and just kept Lock’s ideas. Thus he held that things just consist of ideas. There are two things about ideas: they only exist when being thought of or perceived, and they need minds to exist in. So, as Berkeley did not think material things consist of matter but only of ideas, it followed that they only existed as long as they were being perceived. How, for example, do I know that the plan tree in the garden exists when I am not looking at it? Thus Berkeley said that for a thing to exist is for it to be perceived (esse est percipi). I shall not dwell any further on Berkeley, but he is of some importance because his theory returned with Bertrand Russell, who had a great influence on British philosophy in the 20th century.
We now come to David Hume, the greatest of the British empiricists, who lived most of his life, except for two spells in France, in Edinburgh, where he was born in 1711 and dies in 1776, very much a man of the Enlightenment. Hume began his Treatise of Human Nature, written in his mid-twenties and published before he was thirty in 1739 – 40, by wanting to confine the meaning of “ideas” to thought. The primary principle of Hume’s philosophy, from which all else follows in it, was that the only existences we are immediately aware of are perceptions. Perceptions in Hume include sense impressions and ideas. All ideas are derived from sense impressions and are just faded impressions. It thus follows that Hume did not have a place for general concepts: concepts for Hume were mental images. Thus Hume reduced the mind more or less to the imagination. He did not, for instance, think that reason could produce any new ideas, because ideas were derived from impressions. The result of limiting the power of reason like this is scepticism. Hume did not think that we have general concepts because, he said, whenever I think of horses it is always of a particular horse. Aquinas too thought that we need to turn to impressions in order to think of things, say of a horse, but, unlike Hume, he also thought that we can go beyond impressions and images to form a general concept of what a horse is, its nature. Hume’s philosophy ironically leads to scepticism, although empiricism is based on what we know with the senses, because once you say that what we know immediately is our sensations rather than real things themselves, then it is difficult to know whether external objects exist. As Hume said, we just infer that they exist without being able to know for certain. Hume’s scepticism of course descended from the scepticism of Locke about the external world.
Like Berkeley, Hume did away with substances, which he said were mere chimeras. But where Berkeley retained Locke’s ideas and said that things consisted of ideas, Hume kept Locke’s qualities and held that things consisted of their qualities: things, objectives, were bundles of qualities for David Hume. It is difficult to explain the unity of things in this way, for what makes anything one if it is just a collection of qualities. Likewise, Hume thought that, as all that we directly know is perceptions, and as perceptions can be conceived distinctly, so they can exist distinctly and do not need a mind to inhere in. When we talk about the mind, according to Hume, we just mean its contents: the mind is nothing other than its contents. There are two difficulties about this. First, what unites a lot of thought so they all belong to one person? Hume’s answer was by “the association of ideas”, a frequent phrase today in sociology, psychology, etc., which goes back to Hume. Second, how do I have the power to think anything and have a first thought unless I already have a mind. Thus the mind precedes: it is not made out of thoughts but produces them.
One last point about Hume. Hume thought that we could observe how one perception causes another but not that we could know that one things causes another. This was because Hume only allowed one kind of cause, a necessary cause: we could only know one thing caused another if it always happened like that, but we cannot know this because it might fail to happen in the future. The sun might not rise tomorrow. Hume had drawn the definition of cause too tightly. Not everything caused is necessary: for instance, a painting is caused by an artist but he paints it by his free choice. When we call two things cause and effect, Hume said, we mean that they usually go together: for example, smoke and a fire. Cause was another name for “constant conjunction” in Hume’s view. One would expect empirical philosophy to be particularly suited to natural science which is empirical, but, if we cannot know causes, empiricism does not serve natural science, which began as the search for causes. Hume did not think we could know causes but, as Anthony Kenny has pointed out, if there is one thing experience teaches us, it is the uniformity in nature. As a result of Hume’s scepticism, it has become fashionable today to deny causes, even among scientists, but this is quite contrary to the aim of natural science.