The validity of knowledge
• Ideal knowledge is absolutely certain.
• Major question: What can we know for sure?
• A minority of knowledge can be conclusive (the earth is round).
• The great majority of (general) knowledge is conjectural, tentative, hypothetical (Popper).
—Can be disproven but not proven.
—Results of testing are retaining or rejecting.
• Specific pieces of evidence can often be settled better than general ones can.
• Therefore, we must start studying the JFK assassination by asking what we can know for sure about it.
• Only then can we ask what is highly probable (but not certain) about it.