Excerpt from this month's featured book by Philip Graham Ryken, "Is Jesus the Only Way?"
The reason philosophical pluralism makes Christians ornery is that it would force them to abandon truth. There are at least four essential beliefs that Christianity refuses to leave behind: the unity of truth, the uniqueness of Jesus Christ, the reality of sin, and the absolute necessity of the atonement.
The Only Truth
Christianity rejects philosophical pluralism because it accepts the Truth, with a capital T. There is only one truth, and that truth is one. As the apostle Paul explained, "We cannot do anything against the truth, but only for the truth." (2 Cor. 13:8).
The Archbishop of Canterbury and the actress Jane Fonda once had an exchange that illustrates how Christians understand truth:
Jane Fonda: "Maybe he is for you, but he's not for me."
The Archbishop of Canterbury: "Well, either he is or he isn't."
Jane Fonda evidently believes in philosophical pluralism. Perhaps her view should be termed "Fonda-mentalism." What is true for you may not be true for her, and vice versa.
As a Christian, the Archbishop of Canterbury rightly insisted that truth cannot contradict itself. Either Jesus is the Son of God and the Savior of the world, or he is not. It is one or the other; it cannot be both. To believe that two contradictory religions are both true is like saying, "2 + 2 = 4, or 5, or 37, or whatever you like." To believe all religions simultaneously is to become hopelessly entangled in self-contradiction. One simply cannot accept the Hindu belief that there are 3000,000 or more gods and at the same time accept the Muslim belief that there is only one god. Nor can one embrace either Hinduism or Islam and Buddhism because historic Buddhism does not believe in a personal God at all.
Or consider religious opinions about the afterlife. Buddhists seek Nirvana, the complete absence of desire. Christianity teaches that heaven is a place where all pure desires are satisfied in Jesus Christ (rev. 22:4). Who is right? If there is a heaven at all, does it negate or satisfy desire?
Opinions about judgment differ as well. Christianity teaches that "man is destined to die once, and after that to face judgment" (Heb 9:27). Hindus believe in a seemingly endless series of reincarnations. Well, which is it? Both views cannot be true.
Religion is not a preference. Although people are allowed to hold their own opinions, they cannot make up their own truth. This cannot be done with religion any more than it can be done with mathematics. To insist that all religions are equally true is another way of saying that all religions are equally false. Somewhere in his Religion and Society Report, Harold O. J. Brown has observed that pluralism "purports to respect all ideas and opinions, but in the last analysis ends by denying that any idea or any conviction has validity." If every religion is compatible with its opposite, why bother with religion at all?