There are certain preliminary observations which should be made before we can take up the question of codifying international law or the method of codification, for without a correct understanding of certain matters, which may be considered fundamental, we may not know whether we are to deal with a system of law or a system of philosophy. As a matter of fact we are dealing with both, for law develops unconsciously or consciously in accordance with the principles of philosophy. If the law of nations is to be considered law in the strict sense of the word, we must deal with it as a system of law. If, on the other hand, it is a system of philosophy rather than of law, we must deal with it as philosophy, and the point of approach and the method of treatment will be different. But, above and beyond law, we are dealing with justice, and with those principles of justice, which, expressed in rules of law, we call the law of nations. Justice is the source; the principles of justice applicable to the conduct of nations constitute the law of nations, and the rules of law based upon these principles change with conditions, or to meet new conditions, and form the body and substance of international law at any given period.