In order to discuss the general function of the logo, we must firstly identify and define the environment where this will have to fulfill its function. The environment is called brand and the definition is as follows: the brand is a collection of ideas and images, a collection that constitutes an undivided whole meant to transmit and sustain the values of a company, a product or a service. As you have noticed, this definition has brought into discussion two defining elements: idea and image. I’d like to emphasize that it is important to follow this order: ideas come first and images are born out of ideas to visually represent them. Once we have known the environment and its definition, we can discuss about the functions that the logo must fulfill.
The first function: the logo defines and incorporates values.
The logo must be designed according to the values which we want it to transmit. As the visual impact can mean much more than a description and the logo will [probably] be the most important visual element, it is recommended that it is given its due importance.
The second function of the logo is to communicate values.
The logo does the communication between the company and the consumer and, besides the product itself, it is the first element that presents the service provider.