If something is scalable, a change in its size will not change its nature. Thus, a triangle is always a triangle, however large or small it is. In contrast, an elephant shrew could not be scaled up into an elephant; its skeleton would not be strong enough, its metabolism unworkable; do see http://www.av8n.com/physics/scaling.htm. If there is a relationship between two scalable entities which can be expressed as a law, such as the ratio between the length of one side of a square to its area, then that relationship will hold good whatever the scale they are both at, and that law is a scaling law. With a scaling law, it is possible to compare information collected at one scale with information at a different scale, and to predict outcomes at different scales.