When I first became interested in philosophy, I was fascinated by two metaphysical issues in particular. The first was the existence of God in the philosophy of religion. How could we prove the existence or non-existence of the greatest possible being that is worthy of religious worship? I was impressed by philosophers' efforts to answer the question over thousands of years. The second was the mystery of phenomenal consciousness in the philosophy of mind. How could the phenomenal aspect of perceptual experience be realised in the brain, which is nothing but an aggregation of billions of neurons? I was amazed by philosophers' elaborate attempts to analyse and solve this deep metaphysical problem. The goal of this work is to bridge these problems in two distinct areas of philosophy by considering ‘knowledge arguments’.

This work is divided into four parts. In Part I, I consider the conceptual background of knowledge arguments. I explain what knowledge arguments are and maintain the following: not only Thomas Nagel's bat argument and Frank Jackson's Mary argument in the philosophy of mind, which purport to refute the physicalist approach to phenomenal consciousness, but also Patrick Grim's argument from knowledge de se and the argument from concept possession in the philosophy of religion, which purport to refute the existence of God, are rightly regarded as knowledge arguments. In Part II, I focus on these knowledge arguments in the philosophy of religion. I try to undermine existing objections to the arguments and provide my own new objections.