Franklin Merrell-Wolff raises the possibility of certain knowledge in the dualistic world. In particular, he directs this question toward three forms of cognition: sensuous cognition, conceptual cognition, and introceptual cognition. He provides a critique of the scientific method, and points out that empirical science gives pragmatic truth, but not certainty. Wolff then relates several amusing anecdotes to demonstrate that the senses do not give certainty. He goes on to analyze the conceptual power of cognition and notes that even in mathematics our thinking is based on postulates or axioms that are not self-evident. He also notes that the foundation of mathematics includes a number of paradoxes. Wolff submits that the only certain knowledge is that knowledge which is awakened by introceptual cognition; however, he points out that there is an unavoidable error in transcribing this knowledge into sensuous or conceptual terms. Accordingly, he concludes that one must concede the possibility of error or failure in our knowledge, but nonetheless encourages us to dare to accept the challenge of the Great Adventure.