What did Mary know? Russellian Monism without intrinsic properties

The Mary thought experiment aims to demonstrate that science cannot capture what experiences feel like. Russellian Monism (RM) avoids this problem by claiming that phenomenality is an intrinsic (non-relational and non-dispositional) property of matter and beyond the scope of science, which is limited to describing extrinsic (relational and dispositional) properties. This notion of intrinsicality is tied to categoricalism, and I call it “Strong Intrinsicality”. I argue that strong intrinsicality is problematic. First, it is not compatible with neuroscientific theories where experiences are considered as causal processes. Second, I argue that if the phenomenal properties have causal power, they can also affect neuroscientific measuring devices and be scientifically modeled, in contrast to what RM holds. I argue that we can preserve the Kantian core of RM without commitment to Strong Intrinsicality, which can be replaced with Weak Intrinsicality, meaning model-independence. Science is confined to observing and modeling entities, whereas an experience is the concrete, model-independent process which is modeled by science as, for example, “neural process”. Science cannot capture the phenomenal quality of an experience, because that is part of its model-independent or weakly intrinsic nature. On the proposed account, the epistemic gap is the difference between a model and the modeled.