Juries must, of necessity, be governed, in reaching many results through inferences from other facts, by certain laws of nature and human reason. They are often obliged to infer one thing from another, and this, whether that other be a fact direct or circumstantial.
Laws fixed, certain, and uniform, are said to be the distinguishing traits of civilized from savage communities. In these last, seldom are any laws, unless it be the arbitrary and uncertain will of the strongest.