1 What does 'knowledge' mean?
As long as our intuitive grasp on the term 'knowledge' was held sufficient to cope with most practical purposes, no urging need was felt to overcome the limits implied by inadequacy to verbally express the meaning of the term.
For some time now, attitudes have changed. Arguments like Searle's Chinese room, and the need to include forms of non-human knowledge, fueled a debate.
However, a rigorous, explicit definition of the term 'knowledge', based on introspective examination of the concept, remained elusive, most attempts resulting in tautology and petitio principii.
Investigation on the concept, carried out by examining the internal criteria which decide/recognize whether or not a process constitutes knowledge, has mainly been based on introspection. However, an alternative strategy could be pursued on physical ground. Actually, if the criteria, as supported by Postulates 1 and 2 and Lemma above, are coded in the brain, a detailed description of the neural assemblies involved and of their material ways of action would yield an explicit, unambiguous and exhaustive definition of the term 'knowledge'.
Such an achievement, although clearly out of our reach now and in the next future, appears in principle attainable. Alone, this awareness can deeply change our perspective, in the same way as attention to the neural pathways of sight changed our approach to vision.
A 'neural definition' would be fully expressed verbally and rigorously verifiable, with great advantages over +an introspective one. A degree of precariousness could remain in both cases, however, linked to the object represented, liable to adaptive modifications in time, obsolescence, or even disappearance (as occurs now to the definition of 'soul', for instance). Due to this, the initial question could be more correctly rephrased as: What does 'knowledge' mean now?