O. Ouellette

“And the Buddha pointed out that his confusion was justified, for 'the dharma is profound, difficult to see, difficult to understand, peaceful, excellent, beyond the sphere of logic, subtle, and to be understood by the wise'. The reason for this is that it is not readily comprehended by one who holds a different view and has different learnings and inclinations, different involvements and instruction. It is clear from this statement that the conception of nibbāna in beyond logical reasoning, not because it is an Ultimate Reality transcending logic, but because logic or reason, being the 'slave of passions', makes it difficult for one who has a passion for an alien tradition to understand the conception of nibbāna.”
― David J. Kalupahana, Buddhist Philosophy: A Historical Analysis