Standards of critical evaluation

From its beginnings in Greece over 2,500 years ago, Western philosophy and science have been primarily public
activities. Some of the best minds of each generation have presented their views on important issues for their
fellow citizens to accept or reject. Using only the forces of reason and eloquence to persuade, rather than torture
or threats of death or damnation, the critical thinkers of the past developed rules and guidelines for determining
beliefs and actions. Their predecessors or contemporaries relied on the authority of ancient texts and customs, or
on the power granted them by their social position, to coerce agreement. Critically thinking philosophers and
scientists used evidence available to all as they sought to discover the truth and to persuade others to accept their
discoveries.
It is true that often the arguments and disputations of philosophers have been over questions that are
unanswerable in any final sense. It is also true that there is no universal agreement about the methods and standards
of evaluation used in these disputes. Nevertheless, much progress has been made in understanding not only the
scope and limits of possible knowledge, but also the bases for reasonable belief. Three of the most important areas
of philosophy relevant to critical thinking are logic, epistemology, and ethics. The first two have long and important
histories of making significant contributions to the methods and standards of evaluation now prevalent in
science, law, and philosophy. Ethics is most important for its contributions to the standards for evaluating the
morality of actions. Logic studies the principles of valid and invalid reasoning. The domain of
logic is narrower than the domain of critical thinking, which is concerned with evaluating the justification of
beliefs and actions. Epistemology studies the origin, nature, and limits of knowledge.
Socrates
One philosopher stands out as having had the greatest influence on our critical thinking standards: the Socrates
(469?–399 BCE) of Plato (470-347 BCE). “The unexamined life is not worth living,” says the Socrates of Plato’s
Apology. The Socrates known to us is a figure from Plato’s dialogues. For centuries, Socrates has stood as a model
of intellectual integrity and inquiry: the ideal critical thinker. It is not any particular idea that earned him this
reputation. It is his method of questioning and cross-examination of positions that is taken as an ideal for critical
thinking. The technique is known as the Socratic Method--named after the technique he used in Plato’s earliest
dialogues such as Gorgias, Euthyphro, Apology, and the first part of the Republic. In those dialogues, Socrates
takes up such issues as the nature of virtue, piety, or justice, and through a series of questions examines the meanings
and implications of various views expressed by others. In each case, Socrates is depicted as confronting
someone who claims to be an expert. Each expert is depicted as arrogant and self-righteous, without the slightest
self-doubt. Socrates leads his antagonists not to the answer but to confusion. What Plato seemed to admire about
Socrates was not only his method of cross-examination, but also his humble and skeptical attitude. That attitude
was in stark contrast to the arrogance of the priest Euthyphro or the sophist Thrasymachus. Socrates meaning is
clear. The arrogant do not examine their views. They are not worth imitating.
Of all Plato’s works, perhaps the best known is his Apology, the account of Socrates’ trial for impiety and
corrupting the youth of Athens. Nothing else Plato wrote has had a more profound effect on the intellectual attitude


of philosophers who came after him. In the Apology, Socrates is depicted as defending his way of life, rather than
defending himself against the charges against him. In one of the most eloquent works in Western literature,
Socrates defends a life of constant inquiry and examination of beliefs and actions. Finally, Socrates assures his
accusers that the death sentence handed down to him would guarantee that he would be known to history as a
heroic figure, one who died for the “crime” of thinking for himself and for encouraging others to do likewise.
Socrates may have been put to death over two thousand years ago, but his spirit of critical inquiry lives on. One
of Socrates’ main critical concerns was clarity. Of course, standards of clarity change. As we have become more
aware of the power and functions of language, we have become both more demanding in our quest for clarity and
more understanding of the limits of language. Simultaneously, those who would like to manipulate the thoughts
and deeds of others (advertisers, politicians, con artists, evangelists, talk show hosts, lawyers, cult recruiters, and
the like) continue to use their creative powers to persuade us to believe or do things that remain unclear to us.
Today, the study of clarity requires a companion study of the persuasive techniques of modern propagandists,
especially their attempts to manipulate thought and action through the clever use and abuse of language. Chapter
Two will examine these and other issues concerning language and critical thinking.
Socrates was not concerned with clarity for its own sake, however. He knew that without clarity we couldn’t
understand what it is we are being asked to believe or to do. But he also recognized that clarity is not enough to
base any belief or action on. Today we recognize that in addition to being based on clear claims, a critical thinker’s
beliefs and actions should be based on accurate information. Information can only be as accurate as the source
from which it comes. Chapter Three examines the issue of sources. If we can’t discover something for ourselves,
what criteria should we use to determine the accuracy and reliability of sources, especially sources who claim some
sort of special expertise or knowledge? How accurate is the mass media, one of the main sources of information for
many of us?
Other chapters will concern such questions as what makes a reason a good reason for believing something or
for taking some action. Or, what makes any reason or set of reasons adequate to justify believing something or
taking some action. Since, at the very least, a good reason must be relevant to justifying a belief or action, the
issue of relevance is one we must take up. Good reasons must also be sufficient to warrant accepting a belief or
taking some action. Hence, the criteria by which we judge the sufficiency of evidence are going to be examined in
detail, including how much weight should be given to each piece of evidence. We’ll also consider the completeness
requirement: that pertinent evidence not be suppressed or ignored, that everything relevant to the issue be presented.
It was good that you, as our hypothetical airport safety manager, took every bomb threat seriously. But you
should have considered all the relevant evidence, including the fact that people sometimes lie to further their own
ends. You should have made some effort to get more information about the source of the tip. Relying on the
psychic’s self-proclaimed talent on a television show is not sufficient.
Knowing and adhering to the standards of critical thinking will take us a long way toward becoming a critical
thinker. But if we don’t have the right attitude, we may fail despite our knowledge of the standards.