This article proposes some reflections about the status and the role of representations within cognition. It compares the traditional physical symbol system hypothesis with the more recent anti-representationalist approach. After a discussion about the definition of the notion of symbol, some arguments are proposed for illustrating the role of external structures in determining our cognitive behavior and a broader definition of representation is advanced. The last part of the article is devoted to illustrate the epistemic role of some interactions between agent and environment.