Levels of reality

These are actually levels of order within matter. At the fundamental level we have fundamental particles. These particles have their own properties, tendencies and laws of behavior. Using these laws and tendencies they form structures like nucleus and atoms and their movements are also determined by non-deterministic laws expressed in probabilities. At this level we have physics that describes the reality. When these atoms combine to form molecules they also acquire new behavior and these new rules can not be derived from the rules used to describe the atoms and sub atomic particles. Since molecules have structures that have their own reality, which determines how they combine and react, they require their own rules and laws - applicable to these structures. Since these structures do not exist at atomic level, molecular laws can not be applied to atoms. Thus chemistry is the science that describes this second level of reality, so as to speak.