These include propositions about : -LRB- a -RRB- an inquiry , -LRB- b -RRB- a method of obtaining knowledge through systematic doubt and continual testing , -LRB- c -RRB- the arbitrariness , relativity , or subjectivity of moral values , -LRB- d -RRB- the limitations of knowledge , -LRB- e -RRB- a method of intellectual caution and suspended judgment .

These include : -LRB- a -RRB- an inquiry ; -LRB- b -RRB- a method of obtaining knowledge through systematic doubt and continual testing ; -LRB- c -RRB- the arbitrariness , relativity , or subjectivity of moral values ; -LRB- d -RRB- the limitations of knowledge ; -LRB- e -RRB- a method of intellectual caution and suspended judgment .
