What is knowledge?

What is knowledge?

The branch of Philosophy concerning the nature of knowledge is Epistemology. Philosophers commonly identify three types of knowledge:

1). Procedural knowledge

2). Acquaintance knowledge

3). Propositional knowledge

Procedural knowledge is ‘knowledge-how’. Think of it in terms of skills: I know how to ride a bicycle.

Acquaintance knowledge is ‘knowledge-of’. Think of it in terms of familiarity based upon encounter: I have known Socrates since he was a boy.

A proposition is an important concept in Philosophy: it means a statement (assertion or claim) that is true or false. Propositional knowledge is ‘knowledge-that’. Think of it in terms of knowing facts: I know that if you heat water to 100C at sea level then it boils.

Propositional knowledge is the main type that philosophers are interested in. There is a long tradition, dating back to Plato in Ancient Greece, that propositional knowledge may be defined as Justified True Belief:

a). There is a belief, eg. Humans are mammals;

b). The belief must be true, eg. Humans are indeed mammals;

c). The belief is justified, eg. Humans have the physiological characteristics of mammals.

There is some controversy over the nature of justification and whether additional requirements are needed to the tripartite definition. For instance, the belief cannot be made true by pure luck. Consider this:

I believed that the winning 4-D lottery number would be 1003.

It was 1003!

The gambler had a belief: the winning 4-D lottery number would be 1003. The belief was true: 1003 came up.

But was the gambler justified in having that belief, or was the belief true merely by luck? In either case, the gambler takes home the money…

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