 But for natural science to achieve the status of a science, it presupposes the capacity of human beings to know things apart from their particular individuating characteristics (though not apart from the existence of matter), i.e., natural philosophy. Natural philosophy ‘gets behind’ phenomena in order to discover essential connections and causes. Thus, from that which is presented in sense perception, the mind constructs an object (the essence) which is universal. (This is possible because, Maritain maintains, there are essences or natures of things.) This process of ‘thinking through’ to the nature of the thing is called by Maritain dianoetical knowledge. So, while natural science and natural philosophy both focus on the physical, the natural philosopher—unlike the scientist—is concerned with the essence of the object and its definition (or, at the very least, an account of its various properties). This is knowledge at the level of the first ‘degree of abstraction’.