Stenger was an advocate of philosophical naturalism, skepticism, and atheism. He was a prominent critic of intelligent design and the aggressive use of the anthropic principle. He maintained that if consciousness and free will do exist, they will eventually be explained in a scientific manner that invokes neither the mystical nor the supernatural. He criticized those who invoke the perplexities of quantum mechanics in support of the paranormal, mysticism, or supernatural phenomena, writing several books and articles to debunk contemporary pseudoscience.