[galaxyLogic]

I'm wondering, isn't Information Theory as much part of physics as Thermodynamics is?

[kgwgk]

Would you say that Geometry is as much a part of physics as Optics is?

[ajkjk]

Not really. Information theory applies to anything probability applies to, including many situations that aren't "physics" per se. For instance it has a lot to do with algorithms and data as well. I think of it as being at the level of geometry and calculus.