1.3) First Definition

Most people would agree on the following definition (as a first try):

A model is a simplified representation

But why do we simplify? In most cases, because we need to solve a problem and the information, data, time, man-power, or money needed to consider every aspect of the problem is constrained. Therefore we use simplified models to solve our problem under these constraints and we can say that:

Modelling (=the process of developing a model) is:

Problem solving under constraints