Analogical argument is based on the sameness or similarity of two objects in some attributes, and infers that the two objects are also the same or similar in other attributes  Its logical form is that object A has the attributes of a, b, c and d  Object B has properties of a, b, c
So object B has the property of d
Both light and sound have the phenomena of linear propagation, refraction and reflection, so light, like sound, also has fluctuation