A Clearer Example

The Flowers Of Guidance Volume One Nine Instructive Steps to Gaining Knowledge Step 4: Light of knowledge
A mechanic who has learned the mechanical secrets of a vehicle, can operate on any type of vehicle, and is informed of any apparatus and systems in a vehicle.

I will give a more explicit example: A person who learned how to drive and became a mechanic did so by driving and working on a Volkswagen. After learning to drive a Volkswagen, he then could understand the basics of driving any other car with some knowledge and attention or even become an expert in its mechanics. This example shows how there are some similar and general principles in all sorts of vehicles. This notion explains why auto-repair shops can repair all sorts of vehicles, even one with the newest technologies and innovations. Simply because the general principles are one and united, and appearance in differences yields to true unity.