The aim of this dissertation is to come to terms with information talk in biology. To this end, I critique the existing philosophical literature and offer a positive account that seeks to understand biological information in terms of function. My key points are that: (1) biological information is currently understood too narrowly, (2) information talk should be understood broadly including concepts like signal, network, circuit, etc. and (3) biological information is best thought of as characterizing a particular kind of biological function in which a biological system uses a proxy to indicate a state of affairs or the value of a variable.

I begin by arguing that the philosophical literature is too narrowly focused on the meaning of the term information and that it is too restrictive about what counts as an adequate justification of information talk in biology. Chapter three argues that Griffiths and Gray's parity thesis fails to adequately capture what Shannon and Dretske had in mind with their definitions of information. This failing undermines Griffiths and Gray's argument (and Griffiths' subsequent arguments) for the parity thesis. Chapters four and five develop accounts of signal and information respectively that seek to explicate standard biological research practices. Chapter four looks at the informational term that plays the largest role in contemporary biology—signal. Signal is analyzed in terms of the idea that a signal characterizes a particular kind of biological function in which an entity is used by a biological system to indicate a change in a state of affairs so the system can respond appropriately. Chapter five generalizes on this idea to provide a general description of biological information using the same core idea.