Metaphysics of knowledge

DOI: 10.4324/9780415249126-P066-1
Version: v1,  Published online: 2017
Retrieved April 20, 2021, from

3. The realization of knowledge

If, as Williamson (2000), Nagel (2013) and others contend, knowledge is a mental state, the question arises of how states of knowledge are physically realized (see Functionalism). Shoemaker (2007) and Wilson (2001) distinguished between a total realizer of a property, that is, a property whose instantiation is metaphysically sufficient for the instantiation of the realized property, and a core realizer, that is, a property whose instantiation is a salient part of a total instantiation of the realized property. Salience is understood in terms of the specific part of the physical system most readily identified as playing a causal role in producing or sustaining the realized property. A total realization of a property is constituted by the core realization, plus the non-core part of the total realization, where the non-core realizer is the part of the system which needs to be activated if the core realizer is to play the causal role in question. Moreover, background conditions pertain to general features outwith the system, but necessary for its existence and functioning. These conditions should, strictly speaking, be included in the total realization. Importantly while the realized property is one that an agent has, the physical system need not be identical to the agent. The total realizer of a property is then a property of the system, containing any given core realization as a proper part.

Wilson (2001) proceeds to define three types of realization. Narrow realization is a total realization whose core and non-core parts are located within the agent who has the realized property. Digestive and other physiological systems exemplify this type of realization. The properties these systems realize are individualistic as they concern organismic features of the agent. Wide realization differs from narrow realization in that the non-core part is not located entirely within the agent who has the realized property. These are cases where the system extends beyond the bodily boundary of the agent who has the realized property. Ecological systems such as the predator–prey relationship are cases in point. Finally, a radically wide realization is a wide realization whose core part is also not located entirely within the agent who has the realized property. Both parts of the total realization are wide by way of extending beyond the bodily boundaries of the agent. Examples include social actions such as voting where the electoral system extends beyond the boundaries of individual voters.

How is the mental property (or state) of having knowledge physically realized in this model? Knowledge is typically attributed to an individual agent as in the case of ordinary perceptual knowledge. In that case, knowledge is widely realized in that the agent forms part of the realizing system, rather than narrowly realized as when the system forms part of the agent. More precisely, such knowledge has a wide total realization, because (parts of) the non-core parts of its total realization are located outside the agent. For example, the factivity of knowledge, or the reliability of the belief-producing process, or the absence of environmental epistemic defeat, are all worldly features that need to be in place for the core realizer of knowledge states to fill its causal role. Still, such knowledge arguably has an individualistic core realization. Thus, Sosa’s virtue epistemology (2007: 29) has it that knowledge is belief that is true through cognitive ability, where such ability is typically thought of along individualistic lines as being located where the agent is and as having a physical basis resident in the agent (see virtue epistemology). For example, an agent has perceptual knowledge on this view just in case the agent believes truly because of exercising abilities which are physically based in the agent’s own perceptual apparatus. The proposal would then be to identify this physical basis with the core realizer of the agent’s knowledge.

The extended mind hypothesis, introduced by Chalmers and Clark (1998) and defended at length by Clark (2008), says that active features of the proximate environment, for example smartphones, in part constitute cognitive processes or mental states. That happens when an agent is linked with an external entity in a two-way interaction, creating a coupled system which counts as a cognitive system in its own right. This view implies that (parts of) the core realization base for mental states spatially expands to involve environmental resources. Consequently, only radically wide realization will fit the bill. For what is required for extended mental states is that (parts of) the core parts of a total realization are located in the surrounding environment. The core part is what most saliently has to do with playing the causal role of the mental state in question, and cognitive extension is precisely about the active role of environmental resources in driving cognitive processes. States of knowledge may be similarly extended, or so Pritchard (2010) and Carter and Kallestrup (2016) argue. Extended knowledge is also radically widely realized in that not only do (parts of) the non-core parts of the total realization of such knowledge reside outside the individual agent, so do also (parts of) the core parts of that total realization.

Note that even though radically wide realization requires wide systems, it is consistent with the existence of narrow agents – that is, the radically widely realized property is instantiated by the individual agent rather than the system. But a number of social epistemologists, for example Lackey (2014) and Bird (2014), argue that some groups and institutions have knowledge over and above any knowledge had by their members (see Social epistemology). Thus, a suitably organised research team whose individual intentions to action are joined together may acquire scientific knowledge that none of its members could attain on their own. See, for example, Schmitt (1994) and Pettit and Schweikard (2006). Such a wide system would call for wide (group or institutional) agency. Indeed, if the research team interacts with sophisticated scientific equipment in such a way as to form a coupled system, then the team may be said to possess extended scientific knowledge, which would itself be radically widely realized.

Citing this article:
Kallestrup, Jesper. The realization of knowledge. Metaphysics of knowledge, 2017, doi:10.4324/9780415249126-P066-1. Routledge Encyclopedia of Philosophy, Taylor and Francis,
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