In asking what it means to be an empiricist, the present volume does not seek to provide a definitive or authoritative introduction to the foundation and establishment of empiricism. Instead, our objectives are to deconstruct some misleading preconceptions and to propose some new perspectivess on this much used but still somehow ambiguous concept. It marks the beginning of a new reflection rather than a conclusion. Throughout this volume, we aim to present empiricism as the result of two parallel dialogues. First, it was born out of an exchange between several distinc observational and experimental traditions in Europe. We therefore advocate speaking in the plural about empirical methods, underlining the distinctions between local uses and grand, national standards, while also highlighting the complex discussion around the values and norms of empiricism. Secondly, it emerged as part of a dialogue between several positions within the theory of knowledge which for too long have been reduced to a simple dualism. The most important lessonto be learned from the eighteenth century is that there wasn' such a thing as a war between rationalism and empiricism, but rather a constant attempt to accomodate both. This forces us to conceive of a more complex and fruitful relationship, but also a much more interesting one.