General terms:
* Learning
* Inquiry
* Exploration
* Research
* Investigation
* Study
* Discovery
* Understanding
* Elucidation
More specific terms:
* Epistemology (the philosophical study of knowledge)
* Scholarship (formal study and research)
* Cognition (the mental processes involved in knowing)
* Inquisitiveness (a natural desire to learn)
* Curiosity (a strong desire to know or learn something)
* Intellectual pursuit
* Academic pursuit
Informal terms:
* Finding out
* Figuring things out
* Getting the scoop
The best alternative will depend on the specific context and the tone you wish to convey. For example, "learning" might be appropriate for a general discussion of acquiring knowledge, while "epistemology" would be more suitable for a philosophical context.