The strongest argument which convinced adherents of determinism put forward is that the admission of freedom of the will does away with the principle of causality within the sphere of personal existence, and makes human activity incomprehensible. “I understand” and “I explain” mean: I apprehend the presentations of experience in terms of the basic forms of thought, and in this way I assimilate them, I register them in the system of knowledge which makes up my intellectual capital. One of these forms of thought, and one of the very highest importance, is the concept of causality: without it the mind would remain perpetually bemused before an orderless world of phenomena, displaying no rhyme or reason, like the world of magic or that of dreams. If, therefore, freedom of the will excludes a principle on which our intellectual well-being depends so “much, it must be rejected by the philosophical mind and given no place amongst the truths which that mind recognizes. There is a lasting validity in Immanuel Kant's observation:“If we grant that morality necessarily presupposes freedom (in the strictest sense) and if at the same time we grant that speculative reason has proved that such freedom does not allow of being thought, then the former supposition— that made on behalf of morality—would have to give way to this other contention, the opposite of which involves a palpable contradiction.”.