It is clear from the Torah that there are obligations of the intellect as well as obligations of action.
I am the Lord your G-d, Who has taken you out of the land of Egypt, from the house of slavery. You shall not recognize the G-ds of others in My presence
The first two of the Ten Commandments obligate us to acknowledge G-d’s existence and His involvement in the world, and to deny the existence of any other power. Every Jew is required to affirm certain truths and to reject falsehood: truth, belief and knowledge are constant themes throughout the Torah.
In the account of the plagues in Egypt, for example, G-d repeatedly states that the purpose of the miracles is to demonstrate certain basic truths about His existence. G-d brings the first two plagues, “so that you will know that there is none like G-d, our G-d.” After the fourth plague, He says, “so that you will know that I am G-d in the midst of the land.” The fifth plague is followed by the statement, “So that you shall know that there is none like Me in all the world.” The Torah makes it very clear that G-d’s purpose in performing the many miracles surrounding the Exodus was not simply to free the Jews and punish the Egyptians. The supernatural events that occurred during the Exodus were designed to be an educational experience (albeit, high-impact) for the Egyptians and for the Jews. They were a graphic demonstration of the true nature of G-d. It is only because G-d wanted to inform the entire world of certain eternal truths that the Exodus took place in such a dramatic and awe-inspiring way. G-d could have accomplished the same results much more easily and efficiently by simply removing the Jews from Egypt and placing them in the Promised Land.
Nachmanides, the 13th century Jewish philosopher from Spain, elaborates on this point:
The intent of all the commandments is that we should believe in G-d and admit that He created us; and that is the purpose of the whole of creation… And G-d’s… only desire in this lower world is that humans should know and acknowledge to G-d that He created us.
Judaism is predicated upon the belief that there are absolute truths that are accessible to human beings.
For this commandment that I command you today — it is not hidden from you and it is not distant. It is not in heaven, [for you] to say, “Who can ascend to the heaven for us and take it for us, so that we can obey it and fulfill it?” Nor is it across the sea, to say, “Who can cross to the other side of the sea for us and take it for us, so that we can obey it and fulfill it?” Rather, the matter is very near to you — in your mouth and in your heart — to fulfill it.
A philosophy of pluralism or moral relativism, which denies the existence of absolute truths, is unacceptable to Jewish thought; the Torah has very definite moral pronouncements, imperatives and laws. The belief that all truth is relative, however, pervades modern society. As noted scholar and social commentator, Allan Bloom writes:
There is one thing a professor can be absolutely certain of: almost every student entering the university believes, or says he believes, that truth is relative. If this belief is put to the test, one can count on the students’ reaction: they will be uncomprehending. That anyone should regard the proposition as not self-evident astonishes them, as though one were calling into question 2 + 2 = 4. These are things you don’t think about
Not only is a relativist often self-deluding, he is often intolerant of those who do believe in absolutes. The former Chief Rabbi of the United Kingdom, Lord Jonathan Sacks, points out that to the same degree that Judaism rejects pluralism, pluralism rejects Judaism:
Theological, as opposed to political, pluralism presupposes the absence of absolute or normative truth and hence the falsehood of Orthodoxy. Orthodoxy stakes its being on the existence of some truth that transcends the relativities of man. This is the rock on which pluralism founders. Either the Torah is the unmediated word of G-d or it is not. Either Halachah [Jewish law] commands every Jew or it does not. Either G-d speaks to us through history or He does not. Where truth and falsity are at stake, the idea that both sides of a contradiction are true is itself a contradiction… the [literature] on pluralism proceeds on the explicit or hidden premise that Orthodoxy is false. It could not be otherwise, for if Orthodoxy is true, pluralism would be false. But if so, pluralism is no more tolerant than Orthodoxy. Each represents a way of viewing the relationship between belief and truth, and each excludes the other.<