system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are so many common philosophical ideas dismissed as Philosophy 101? What concepts are covered at higher levels?
gpt
Most common philosophical ideas are common because they can be communicated and understood without an extensive background in philosophy or specialized vocabulary. Think of the plot of the matrix and its idea that the reality we perceive may not be 'real' at all, this is a very expansive concept but it's summarized very briefly and most people 'got' it without too much explanation.

These sort of ideas are dismissed as 'philosophy 101' because they may be profound and interesting ideas but anybody with one semester of logic and critical thinking probably already knows and understands them. They're entry-level concepts, and being able to comprehend and discuss them indicates a basic familiarity with philosophy in general, not some deep, arcane knowledge.

The higher levels can encompass nearly anything, so it's hard to be specific. The distinction is more about methodology than the subject matter, it's like the difference between looking at a bug under a dissecting scope in fifth grade vs. looking at it under a scanning electron scope in college. You're investigating the same subjects, but more advanced methodology requires more advanced techniques and more experience,and the results are more informative but also harder to understand.