To me enterprise architecture is a branch of engineering, and engineering is the practical application of science. In specific I find system architecture to be a specialization within system engineering and enterprise architecture to be a specialization of that in which the enterprise is the system under study. The science in system engineering and applied to system architecture and enterprise architecture is systems theory (cf Bertanfly and his Nobel Prize).
In the enterprise you cannot understand the goals or direction of that enterprise without economics. One must have a grasp on engineering economics to practice enterprise
architecture. In 1776 Adam Smith wrote "The Wealth of Nations"; In 1904 Max Weber wrote the book "The Protestant Ethic and the Spirit of Capitalism". The enterprise, to me, is an organization within the economy. Enterprises produce something, products or services, consumed by others. Even government enterprises or non-profit organizations must produce. They can do this efficiently or inefficiently.
In enterprise architecture we apply rigor and repeatable method (based on empirical evidence) to the enterprise, especially in regard to making the enterprise more efficient, more productive, in some measurable way. This involves technology: it may be process technology involving only the reorganization of manual human effort but this is still technology.
Technology comes in waves, each following the engineering curve for technology maturity and the hype curve. Waves have become more frequent, spaced closer together. In my career the main type of technology most directly introduced and managed by enterprise architecture are the integration architectures: EAI (Enterprise Application Integration), ESB (Enterprise Service Bus), MOM (Message Oriented Middleware), messaging appliances and grids, enterprise databases and data integration technologies, workflow, business process management, and SOA (Service Oriented Architecture). Enterprise architecture is therefore most directly linked to these integration technologies.
"If you do anything long enough, you eventually get good at it." MK