Epistemology is a branch of philosophy that studies the nature and basis of knowledge. How do we know things? It also studies the veracity of "truth." How do we know the difference between belief, knowledge, opinion, fact, reality and fantasy? The Greek philosopher, Carneades, believed that knowledge of reality, of what is true or false, is impossible, that nothing can be known with certainty; his philosophy is known as skepticism. It does not reject belief altogether; Carneades felt that our belief about any given matter should be subjected to intense scrutiny and then, using a scale of probability, we should accept or reject the likelihood of its truth or falsehood. But we must make no absolute claims to it. Another Greek skeptic, Cratylus, however, was more radical in his approach and believed that nothing could be known at all, and thus no statements could convey anything true or meaningful. He finally gave up talking altogether. 

Most of us are neither moderate nor extreme skeptics; we believe what our teachers told us. Although some of us learned later that perhaps a little skepticism was indeed warranted, we survived with our grasp of reality reasonably intact. We live in a world where facts are meaningful and opinions can be assessed, at least to the degree that we deem them sound or unsound. When it comes to religion, those of us who are raised in traditions often reject such assessments and simply believe what we were taught. For many religious people, skepticism is anathema, the work of the devil. However, our Abrahamic traditions of Judaism, Christianity and Islam have always been concerned with and seriously interested in epistemology, because each of these faiths have profound truth claims that need substantiation or "believability." 

Islam, at its advent, developed a sophisticated methodology for the validation of truth claims. One of the greatest achievements of the Islamic scholastic tradition is 'ilm ar-rijaal, the science of narrators. It is the study of reports of events in the life of the Prophet, especially of his sayings and deeds. Its formulators established a rigid set of criteria to validate the truth claims of those who asserted they saw or heard the Prophet do or say such-and-such. Reports were grouped into two categories: ahad, or solitary reports in which one or a few people claimed to have heard or seen something, and mutawatir, or multiply-transmitted reports narrated in numbers large enough to preclude collusive fabrication. The solitary reports must meet many criteria before being accepted as sound statements that nonetheless contain, depending upon the degree to which the criteria were met, a certain probability of error. On the other hand, firmly established multiply-transmitted reports, in numbers that rule out collusion, are taken as uncontestable fact. 

The Quran, the seventh century book narrated by Muhammad, is considered mutawatir, and thus epistemologically undeniable. Whether one believes it is from God or not is another matter, but the Quran in its current form is the same Quran the Prophet taught to his companions more than 1,400 years ago; untold numbers in each generation of Muslims have transmitted the same recitation, making it infallible in its historicity and accuracy. Islamic scholars accepted multiply-transmitted reports from Muslims and people of other faiths. Upon this epistemological foundation rests the Muslim faith. Creedal matters are deemed valid only if they are buttressed by multiply-transmitted traditions that can be traced back to the Prophet. Although Islamic jurisprudence is largely based upon solitary evidence (hence the differences of opinion in the various schools), the Quran and the creed of Islam are both founded upon multiple narratives that achieve an undeniable status. Early Muslim scholars would certainly consider much of our current knowledge of history to have achieved such status. For instance, there is consensus among historians that the Normans invaded England in 1066; too many accounts of this momentous event exist and have been recounted in each generation through multiple sources. In the case of any solitary original source, healthy skepticism is warranted. When Lee Harvey Oswald claimed to be a patsy, it led to an entire field of conspiracy studies among Kennedy assassination buffs. Did he act alone or didn't he? That aspect of the event is debatable. But was John F. Kennedy shot on November, 22, 1963 in a motorcade at Dealey Plaza in Dallas? Far too many accounts of that tragic event exist; to deny it is simply to deny reality and have one's sanity questioned. 

Much of what we know about the world and what we accept as truth comes from multiply-transmitted accounts. Let's say I claim that Australia doesn't exist and is merely a figment of our imagination, that its origins lie in a whimsical cartographer in the Middle Ages who decided that such a large ocean needed a land mass. And, when confronted with people who claim to be from Australia and can prove it, I dismiss them as part of a conspiracy of cartographers who wish to perpetuate the myth of their forbearer. I would be laughed at, or ignored, or deemed "certifiable." While this example seems absurd, many people actually believe things just as fatuous and far-fetched. 

Holocaust denial is one such example. As one who has read some Holocaust denial literature, with the poorly reproduced pictures and claims of the orchestration of these scenes in collusion with the U.S. government, I can attest to the tragic gullibility of people who take such literature as historical truth. To return to the Kennedy assassination, if one reads Mark Lane's version that a rogue element within the CIA killed Kennedy, the "facts" seem overwhelming. But if one reads another version that the Mafia killed Kennedy because of his failure to return Cuba to the gambling lords of Italian America, the "facts" also seem overwhelming. Finally, one can read the version that Mossad killed Kennedy because he wanted to force nuclear inspections in Israel, and again the "facts" seem conclusive. Each of these accounts is presented with utter certainty by the "researchers." In the end, reality is manipulated to meet the needs of the mythologist. 

Indeed, we are each entitled to our own opinions, but not to our own facts. And those who present alternative versions of "reality" tend to reject everything that does not suit their theory, and cherry-pick and interpret everything-facts, innuendos or "coincidences"-that does. 

In the case of the Holocaust, the facts are clear and transmitted from multiple sources. Tens of thousands of Jewish and other individuals who survived the death camps and other horrors of Nazi Germany lived to tell of it. Nazis were brought to trial, evidence was presented in court, and they were convicted. Mass graves were found, and gas chambers were discovered, which were clearly not delicing rooms as some callously claimed. The ovens exist and cannot be reduced to an efficient way of preventing cholera outbreaks or disposing of victims of starvation. I have personally met many Holocaust survivors and their children. I have seen tattoos. I have also heard firsthand accounts of the horrific events. The numbers and details of such events may be legitimate areas of research and inquiry for scholars, but questioning whether the events took place at all undermines the epistemological basis of our collective knowledge. Muslims, of all people, should be conscious of this as their religion is predicated on the same epistemological premises as many major events in history, such as the Holocaust. To deny such things is to undermine Islam as an historical event. That a "conference" examining the historicity of the Holocaust should take place in a Muslim country hosted by a Muslim head of state is particularly tragic and, in my estimation, undermines the historicity of the faith of the people of that state. 

In our inherent contradictions as humans, and in order to validate our own pain, we deny the pain of others. But it is in acknowledging the pain of others that we achieve fully our humanity. A close friend of mine, a professor of religion in a Muslim country for many years, recently told me that his wife, an English teacher in that country, had wanted to use Anne Frank: The Diary of a Young Girl as a text for her Muslim pupils. But the school administrators repeatedly denied her request because they deemed it inappropriate reading for young Muslims. It is sad that the current political morass in the Middle East has led to this intolerable refusal to confront a people's collective suffering. Perhaps in acknowledging that immense past of Jewish suffering, in which the Holocaust is only the most heinous chapter, Muslims can better help the Jewish community to understand the current Muslim pain in Palestine, Iraq and other places. In finding out about others, we encourage others to find out about us. It would greatly help our Jewish brethren to know the historical facts of Jewish experience in the Muslim world, which are often heartening and humanizing and very different from their European experience. In our mutual edification, we grow together. 

Hamza Yusuf is a Muslim scholar, lecturer and author, and the co-founder of the Zaytuna Institute in California, which is dedicated to reviving the traditions of classical Islamic scholarship