Perception is the process by which we become aware of the world around us, including our bodies. When discussing perception, two theories readily come to mind; externalism and internalism, which are parent theories of realism and idealism. While the former holds that what can be known about an object exists independently of one's mind, such that whether a man perceives it or not, he continues to observe the law of physics. The latter on the other hand holds that the property of an object exists solely in the mind, and so to be perceived means to exist. This, therefore, means that what is not perceived does not exist. This work, therefore, looks at these theories and concludes that neither of them stands sufficient as it concerns the act of perception, and therefore states that matter exists independent of the mind but needs the mind to perceive them for their existence to be relevant to man, and since the senses are fallible (realist), the rational mind is needed to decipher these matter (anti-realist). This work adopts the analytic method.