Question

Explain two principle thrusts in physics-Unification and reduction

Answer 1

Unification is the act of unifying the different laws for different phenomena in to a single theory that explains all the different phenomena.  

For example: Electricity, light and magnetism are different phenomenon and have different laws of physics for each of them. These are unified under theory of electromagnetism. 

Reductionism on the other hand is the process of breaking down complex system in to simple constituent system so that law of physics can be applied and we can understand the complex system.  

For example: A complex music can be broken down to simple waves so that we can make music from complicated waves.

Answer 2

Unification is the act of unifying the different laws valid for different phenomena in to a single theory that explains all the different phenomena.
Example:- Electricity, magnetism and light are different phenomena and have different laws of physics for each of them. These are unified under theory of electromagnetism; all these three phenomena can be explained from this theory of electromagnetism.

Reduction is breaking down of a complex system in to simple constituent systems to so that laws of physics can be applied on these systems and we can understand the working of the complex system.
Example:- A complex music can be broken down to simple sine waves so that we can make the music piece from the simple tones.