The anthropocentric view taken by Descartes where what was certain in relation to the individual man was more important than what was societally true,I would argue, is not successful; on the basis that nothing in life is certain and the scientific revolution and enlightenment ideaologies which sought to scientifically examine and define as much of human and natural existance as possible was ultimatly replaced with Romantic ideaologies which appreciated the subjective nature of human interpretation.
Descartes theories departed from religious belief that the church defined morality and reality, and instead placed man as a "self-conscious shaper and guarantor" of his reality, defining man as an autonomous entity capable of shaping his own identity. Building on writers like Alexander Pope’s essays on man ‘know thyself presume not god to scan, the proper study of mankind is man. However, in relation to certainty this theory fails dramatically. Man is so subjective in our examinations of ourselves and no two men think and feel in the same way, we are defined by our personal history, the society in which we live and those we interact with.
As such nothing in life can be 'certain' because even certainty is subjective and open to interpretation. When examining certainty in relation to the individual man the question must be asked as to whose certainty is being satisfied? The man considering or the man being considered- and since no two peoples expectations align exactly it is impossible to define certainty on an individual level, and thusly impossible to satisfy.