Essentially that which is only matter, and the sciences that can, through verifiable methods, explore that which we know exists, through the means of...you know, touching, tasting, seeing, and so on...as well as using other instrumentation and so on...is very useful. The question winds up being: ultimately one of: 'Is that all there is?' And going and saying there wasn't even an understanding of matter as we understand it today prior to [...] about the time of Descartes...um, I don't know if the historical argument's the best one to make in that case. But one thing I can say is that thinking that all that exists is that which we can perceive with the five senses is in no way provable –and then if we talk about, 'Well, what is the essence of something?', then we run into a whole other mess. But if we're talking in the context of modernism, where people have gone and become wholly materialistic, the answers become incredibly simple. Incredibly simplistic. And ultimately, I'm not convinced of their accuracy; not only am I not convinced of their accuracy, but I'm not convinced that it's good for humankind in general: because ultimately we're going to wind up killing ourselves off, if all we believe in is that which is material.