Empiricism

empiricism: the view that all knowledge of the world comes to us

through sense-experience; i.e., all knowledge of the

world is a posteriori knowledge

British empiricism—3 main representatives:

· John Locke (1632-1704)

· George Berkeley (1685-1753)

· David Hume (1711-1776)

Locke—

Major theses:

· Originally (at birth) the mind is a tabula rasa (blank tablet).

· The only way that ideas come into the mind is via sense-experience.

· Some ideas represent the real qualities (“primary qualities”) of the external material objects that cause them. The primary qualities of material objects include their size, shape, and weight.

· Other ideas that we associate with external material objects do not represent the real qualities of external material objects but are rather secondary effects of those objects on the mind. These apparent qualities of external material objects are “secondary qualities” and include color, smell, temperature, texture, etc.

Locke’s model of perception (visual)—

physical object ® light rays ® sense organ ® ideas (sense-data:

(e.g., tree) (retina) shapes, colors, etc.)

Problem: How can we know on empiricist grounds that the

material object (the tree) is “behind” the sensory ideas in the perceiver’s mind and is represented by those ideas?

Berkeley—

Major theses:

· We have no idea of material substance as something existing “behind” our sensory ideas.

· Therefore, physical objects (e.g., trees) are nothing more than collections of sense-data. (“To be is to be perceived.”)

· Therefore, idealism is true—i.e., nothing exists except minds and their contents (ideas).

· Ordinary sensory objects (e.g., trees) exist even when we (human beings) are not perceiving them. They exist as ideas in the mind of God, who creates the patterns and order in which our sense-experience occurs.

· Although we have no ideas of minds (our own or other people’s), we have “notions” of minds (mental substance).

Hume—

Major theses:

· The contents of our experience (“perceptions”) consists of “impressions” and “ideas.” “Impressions” are more lively and vivacious than ideas.

· All perceptions originate as impressions. Ideas are “decayed” impressions.

· There are no impressions, and therefore no ideas, of either material or mental substances. (e.g., The self is nothing more than a “bundle of perceptions”.)

· Therefore, we can know nothing beyond the contents of our immediate experience—e.g.,

· We cannot know anything about causation (e.g., that lightning causes thunder), since all we experience are the “constant conjunctions” of events.

o We cannot know of the continued existence of ordinary objects (e.g., trees) when we are not perceiving them.

o We cannot know that our memories represent past events.

skepticism—the view that knowledge of an external world is

impossible