Technology, in order to be human, needs to be informed by a reflection on what it is to be a tool in ways appropriate to humans. This involves both an instrumental, appropriating aspect (‘I use this tool’) and a limiting, appropriated one (‘The tool uses me’). Cognitive Technology focuses on the ways the computer tool is used, and uses us. Using the tool on the world changes the way we think about the world, and the way the world appears to us: as an example, a simple technology (the leaf blower) and its effects on the human are discussed.