Analysis is the process of breaking a complex topic or substance into smaller parts in order to gain a better understanding of it. The technique has been applied in the study of mathematics and logic since before Aristotle, though analysis as a formal concept is a relatively recent development. The word comes from the Ancient Greek ἀνάλυσις. From it also comes the word's plural, analyses. As a formal concept, the method has variously been ascribed to Alhazen, René Descartes, and Galileo Galilei. It has also been ascribed to Isaac Newton, in the form of a practical method of physical discovery. The converse of analysis is synthesis: putting the pieces back together again in new or different whole.