Knowledge, concept of

The word ‘know’ is exceptional for a number of reasons. It is one of the ten most commonly used verbs in English, alongside basic verbs like ‘be’, ‘do’, ‘say’, ‘have’, and ‘go’. It is also the most frequently used term in epistemic evaluation: we speak of ‘knowing’ far more often than we speak of ‘justification’, ‘reliability’, ‘understanding’, ‘wisdom’, and other intellectual traits or epistemic properties. Perhaps most strikingly, the word ‘know’ allegedly has a meaning-equivalent in every human language. Unlike almost every other word in English, linguists have identified ‘know’ as one of a very small number of words that are culturally universal (Goddard, 2010). These facts suggest that knowledge is deeply important to human life.

Knowledge has also held a central place in epistemology. Indeed, the word ‘epistemology’ comes from the Greek word epistêmê, which is often translated as ‘knowledge’. This is not to say that epistemologists are only interested in knowledge. They also investigate epistemic virtues like open-mindedness and intellectual humility, as well as properties of belief like being rational and justified (among many other things). Still, the enterprise of epistemology has largely been an investigation into the nature, significance, sources, and extent of human knowledge.

But what is knowledge? Why do we value it? How is it acquired? And how much of it do we have?

In the late twentieth century, one of the central questions asked by epistemologists was: when does a true belief count as knowledge? It was widely assumed that knowledge is a form of true belief plus some additional requirement(s), such as justification or reliability. While this view about the nature of knowledge is still popular, it came under scrutiny at the turn of the twenty-first century. Instead of thinking that knowledge must be analysed in terms of more basic components like truth, belief, and justification, Timothy Williamson (2000) suggested that we should take knowledge as basic and use it to understand belief, evidence, and other things.

This reversal of the traditional approach coincided with a renewed interest in the value of knowledge. The problem of explaining why knowledge is valuable goes back at least to Plato’s Meno, but epistemologists are now systematically investigating this question. The value of knowledge also bears on one of the most famous of all philosophical problems: scepticism. The history of epistemology is, in large part, an attempt to reply to the sceptic’s claim that knowledge is impossible. But whether we should care about scepticism depends on whether knowledge is valuable. Some philosophers have argued that knowledge has no distinctive value (e.g. Kaplan, 1985), while others have claimed that knowledge is vital for human survival, cooperation, and flourishing (e.g. Craig, 1990).