The difference between the cynic and the skeptic is the difference between epistemology and ethics. It is the difference between brain and body.
Skepticism is an epistemological word.
Cynicism is ethical.
Epistemology is the branch of philosophy that deals with knowledge.
Ethics is the branch of philosophy that deals with morality.
The Greek word skopein — from which the English word “scope” derives — means “to observe, aim at, examine.” It’s related to the Greek skeptesthai, which means “to look out.”
Skepsis and skeptikos are also both Greek and mean “to look; to enquire; to aim.”
Those are the etymological roots of the word skeptic.
Skeptic — or, if you’re in the United Kingdom, sceptic, the difference being purely one of form and not substance — has its origins in the Ancient Greek thinkers who developed arguments which purport to show that knowledge is either impossible (Academic Scepticism) or that there is never sufficient data to tell if knowledge is possible (Pyrrhonian Scepticism).
Academic Scepticism rejects certainty but accepts degrees of probability. In this sense, Academic Scepticism anticipates elements of present-day quantum theory. The Academic Sceptics rejected certainty on the grounds that our senses (from which all knowledge ultimately derives) are unreliable, and reason therefore is unreliable since, say the Academic Sceptics, we can find no guaranteed standard by which to gauge whether our convictions are true. This claim rests upon the notion that humans can never know anything that is absolutely false.
The roots of Academic Scepticism are found in Socrates famous apothegm: “All I know is that I know nothing.” The word “Academic” in “Academic Scepticism” refers to Plato’s Academy, third century B.C.At around this same time, a fellow by the name of Pyrrho of Elis (c.360-275 B.C.), who was connected with the Methodic School of Medicine in Alexandria, founded a school, which soon came to be known as Pyrrhonian Scepticism. Pyrrho’s followers — most notably a loyal student named Timon (c.315-225 B.C.) — were called Pyrrhonists. None of Pyrrho’s actual writings have survived, and the theoretical formulation of his philosophy comes mainly from a man named Aenesidemus (c.100-40 B.C.).
The essential difference between these two schools of Ancient Greek scepticism is this:
The Pyrrhonists regarded even the claim “I know only that I know nothing” as claiming too much knowledge. There’s even a legend that Pyrrho himself refused to make a definitive judgment of knowledge even if “chariots were about to strike him dead,” and his students allegedly rescued him a number of different times because he refused to make commitments.
To this day the term Pyrrhonist is synonymous with the term sceptic, which is also synonymous with the term agnostic (a meaning “without”; gnosis meaning “knowledge”).
It’s perhaps worth pointing out as well that the word agnostic in this context was, according to the Oxford English Dictionary, coined by Thomas Henry Huxley, in the spring of 1869, at a party, in which there was reportedly “much licking and sucking.” According to R. H. Hutton, who was there: “Huxley took it from St. Paul’s mention of the altar to ‘the Unknown God.’”
In truth, however, the word agnostic was most likely first used by a woman named Isabel Arundell, in a letter to Huxley, who stole it from her without credit.
The Oxford English Dictionary (Unabridged, 2004) lists four meanings of the term skeptic, which are as follows:
1. one who, like Pyrrho and his followers in Greek antiquity, doubts the possibility of real knowledge of any kind; one who holds that there are no adequate grounds for certainty. Example: “I am apt to think there never yet has really been such a monster in the world as a sceptic” (Tucker, 1768).
2. one who doubts the validity of what claims to be knowledge … popularly, one who maintains a doubting attitude with reference to some particular question or statement; one who is habitually inclined to doubt rather than to believe any assertion or apparent fact that comes before him. Example: “If every sceptic in Theology may teach his follies, there can be no religion” (Samuel Johnson, 1779).
3. one who doubts without absolutely denying the truth of the Christian religion or important party of it; loosely, an unbeliever in Christianity. Example: “In listening to the arguments of a sceptic, you are breathing a poisonous air” (R.B. Girdlestone, 1863).
4. occasionally, from its etymological sense: a truth seeker; an inquirer who has not yet arrived at definite conclusions. Example: “A sceptic, then, is one who shades his eyes in order to look steadfastly at a thing.” (M.D. Conway, 1870).
The anthropogenic global warming (AGW) debate has catapulted this latter definition to the forefront, yet many purists, like me, who know the philosophical roots of the word skepticism, are not always comfortable using it in this way — mainly because it’s so at odds with the philosophical meaning of the term. Skepticism has over 2,000 years of heavy philosophical baggage, and to call yourself a skeptic in the philosophical sense entails much more than one “who shades his eyes in order to look steadfastly at a thing.”
Language, however, is a living, breathing organism which will and properly should evolve, and it would be very bad indeed to say that skeptic in this latter sense is incorrect. And yet there is another word for this type of skepticism, a word which is much more precise and much less laden: Evidentialism.
True skepticism — which is to say, agnosticism, which is to say, Pyrrhonism — rejects the possibility of all knowledge, and yet it is precisely this that the scientist seeks, and finds: knowledge.
The philosophical skeptic is defined by three words: “I don’t know.”
The scientific skeptic, on the other hand, is (theoretically) defined by rational inquiry — someone who investigates with a disposition to be persuaded and yet does not (in the words of perhaps the most famous skeptical inquirer of them all) “insensibly twist facts to fit theories, instead of twisting theories to fit facts.”
A cynic, on the other hand, is someone who doesn’t believe goodness is possible.
Cynicism is a moral concept, not epistemologic. Which is to say, it’s only indirectly related to the science of knowledge and thought.
The word cynicism originated with a Greek fellow by the name of Antisthenes (not to be confused with Antihistamines, which are something else entirely), who was once a student of Socrates.
Antisthenes had a notorious contempt for human merit and human pleasure, and that is why to this day the word cynic denotes a sneer.
The cynic rejects goodness.
The skeptic rejects knowledge.
That is the difference between the cynic and the skeptic.
Both words, it should also be noted, do however have one very important thing in common: from a philosophical standpoint, they’re each stupendously incorrect.
Note: this article was commissioned and first appeared, in slightly different form, at the Australian scientist Dr. Jennifer Marohasy’s website. The comments there in response to this article are worth reading.