David Hume
(1711 – 1776)
Scottish Enlightenment philosopher, the last of the “Holy Trinity” of British Empiricism. He is best known for his influential contributions to empiricism, scepticism and naturalism. He criticised the dogmatic rationalism of the 17th century, which paved way for Kant and a new method of philosophising. Hume wanted to establish a naturalistic knowledge of the psychology of human nature.
His first work is A Treatise of Human Nature (1739), which upon bad reception he re-wrote into the highly influential and well-known An Enquiry Concerning the Human Understanding (1748). The Enquiry contains one of his most important contributions to epistemology. This is the so-called Hume’s fork, an idea which builds on Leibniz’s distinction of analytic and synthetic propositions (see Leibniz), though Hume’s calls them a bit differently. His distinction is:
– analytic propositions = “relations of ideas”. They are tautological, that is, only verbal truths that don’t provide any new information about the world, just information on the meaning of words and their relations.
—> For example, an analytic sentence “All bachelors are men”, does not tell you much more about bachelors, which you would not know already by calling someone a bachelor (that he is a man, since “bachelor” is a term for an unmarried man).
– synthetic propositions = “matters of fact”. They correctly describe reality and are necessarily based on observation.
—> For example, the sentence “The cat is on the carpet” actually tells you something true about the world, and can only be known by observation.
According to Hume, any proposition can be categorised in this way. However, If it does not fall into analytic nor synthetic category, the proposition is nonsense and useless.
—> For Hume, God is one example that belongs into this category. According to him, the sentence “God exists” is not analytic, since the negation “God does not exist” is not a contradiction (though some philosophers would dispute this, see Descartes or Spinoza’s on the existence of God). The sentence is also not synthetic, as Hume believes we cannot trace the idea of God back to sense data. Therefore, for Hume, the idea of God is empty and statements about God are nonsense.
Beside God, Hume made an important attack on another benchmark of reason and the scientific method, namely causality. He uses the example of billiard balls to demonstrate that we never experience or see causation, but that we only see a correlation of effects and assume that one caused the other.
—> In the example, Hume observes the movement of billiard ball A as it strikes billiard ball B (event X). Following being struck, billiard ball B moves (event Y). According to Hume, the events are separate impressions; and that ball A caused ball B to move (that X caused Y) is an imagined assumption on our part.
According to Hume, we imagine causation on the basis of our experience, but just because X was followed by Y many times in the past, it does not justify our claim that it will do so again in the future (just because we observe correlation between X and Y, doesn’t mean there is causation).
Hume’s discovery has become known as the problem of induction – namely, what makes us certain that the future will behave like the past? Just because we have observed event X being followed by Y many times, there is no guarantee or logical necessity in nature that would suggest Y has to necessarily follow from X.
The concept of causality of one the key ideas of human mind that are needed to understand the world, but Hume concludes that neither reason nor experience can justify the idea of necessary connections (causality) or that the laws of nature will continue to hold tomorrow.
Also, for Hume, there is equally no unified “self” – for him, what we call the self is just a bundle of perceptions and sense data, which are in perpetual flux.
Another important contribution from Hume is the articulation of the is-ought problem:
He found that many writers jump from making descriptive statements (about what is) to prescriptive normative statements (what ought to be, or what we should do). Hume showed that it is not obvious how one can move from a descriptive to a normative statement, that is, there is no necessary connection between facts and values.
—>This refutes positions based on an appeal to nature – just because something exists and is natural (in nature), it doesn’t mean that it is right.
—>For example, humans have evolved to eat meat. Many would argue that we should eat meat, since we have evolved to do so. However, according to Hume, just because we have evolved to do something, it doesn’t mean that we should. That is, it is not right or wrong to eat meat, but to claim that we should is a fallacy.
Hume also importantly contributed to moral philosophy and ethics. In his An Enquiry Concerning the Principles of Morals (1751), he holds that it is not reason, but passions that guide human behaviour. He was also a sentimentalist, and and held that ethics are based on emotion and sentiment, rather than abstract moral principles.