Quick draft (to expand upon later):
1: Ideas purely based on reality (no hypotheticals, no fantasy worlds, no counterfactual thinking, no normative statements). Hypotheticals, fantasy worlds, counterfactual thinking and normative statements (what I call "Irrealis") are considered lies, and the possible functions of pragmatic use, expressing desires or providing entertainment through fiction are ignored. This view is morally nihilistic, as morality is considered a lie, as well as desires in general. The future may or may not be deemed as "real", depending on the exact view.
2: Irrealis is acknowledged for its possible uses (mentioned above) but the existence of such counterfactual or fantasy scenarios is denied.
3: The existence of counterfactual or fantasy scenarios is considered real, and this is a philosophy that actually exists and is called modal realism.
4: Only ideas that may apply to our real world are considered, even if unpopular, or even if an individual may be the only person using that idea (as long as that idea applies to our real world and not just to fantasy worlds). For example, (I personally believe that) "race" is a social construct, and so, for example, the way the US government has categorized race into "black", "white", "asian" and "native american" is totally arbitrary and based on historical and cultural contingencies. That means, it could had been different. In this #4 category, only ideas that apply to our real world are considered, for example, it's possible to create a racial categorization that is the following: blight (includes people that are currently labelled "white" or "black", which are included in this category of "blight" without distinction), non-Japanese Asian, Japanese, native american. It's a perfectly coherent categorization, the reason it wasn't formulated that way is just because of historical and cultural contingencies (and the concept of "race" was formulated for no other reason than justify slavery, by the way, so it was extremely unlikely that a category such as "blight" would ever be conceptualized, even if philosophically coherent). This #4 category, so, excludes things that cannot apply to our real world. For example, "blight" is covered by this category, but blue-skinned humanoids that fire lasers from their eyes are not.