17th century a time of incredibly rapid change, uncertainty. Everything taken for granted in earlier times had changed, was changing, or was about to change. It's uncomfortable to live in such times. We want certainty (one playwright: not to know where one is, where one has been, not to know where one is going: I would rather not live.) Not surprisingly, great thinkers of 17th century turned their minds to task of providing certainty, trying to show how one could know that certain things were true. Foremost among them: Bacon, Descartes, Pascal. These men did an excellent job in suggesting ways one might effectively pursue knowledge. On who follows their methods can have strong assurance that what he/she believes is true.
SOURCES OF KNOWLEDGE
When we claim we "know" something, what are the possible sources of that knowledge?
--Authority
--Experience
--Reason
--Revelation
--Innate
Which most important? Authority. But not so good in 17th century. Why? Authorities all disagree? So, 17th century thinkers begin to look elsewhere.
BACON
Sir Francis Bacon (1561-1626). English writer, diplomat, philosopher. Tremendously important book, "Novum Organum"--the new instrument.
Advocates inductive reasoning, experience as source of knowledge. This alone, not particularly new: Bacon's contribution, advocacy of a systematic use of experience, the experimental method, what we call scientific method.
Classification of knowledge into different fields and subfields.
Warning against idols:
Tribe: because we're humans, sun appears small, don't see all wave lengths of light
Den or Cave: Our own experiences color our understanding, we must get rid of such prejudices
Market: Exchange of ideas with others may lead to circulation of false ideas. In particular, have to watch out for the medium of exchange, words
Theater: Philosophic systems may make false ideas attractive
Freed from idols, experience can guide us to truth. Example from Bacon himself: investigation of heat. List all sources:
Sun's rays
Lightning
Volcanoes
Natural hot springs
Heated liquids
Hot weather
Shaggy substances
Animals
Animal dung, when fresh
Iron disolved by acid
Sparks
All violently rubbed objects
Examining these, we see that heat:
Not caused by being high (heavenly)
Not caused by being low (earthly)
Not caused by density
Not caused by mixture
Not by expansion
Not by contraction
Heat==Movement
Note that such systematic treatment eventually does produce not merely right answer, but answer one can have considerable confidence in. Bacon predicted that such systematic examination of nature would greatly increase knowledge and make lives better.
But, one problem. Works well for sciences. But what about things we really care about? If you were to have answer to any one question, what would it be? Bacon's method no good for such things--so not surprising that other 17th century thinkers looked elsewhere for source of knowledge and certainty.
One such, Descartes.