Both the way we endow our own utterance with meaning and our attribution of meaning to the utterance of others are acts of tacit knowing.
The expert recognition of specimens, the use of probes and tools, the major skills of our body and mind are all based on a meaningful integration of our body and the sensations felt by our body.
A word focally observed — that is as a sequence of sounds or of marks on paper — appears to us as a meaningless external object; while its assimilation, which makes it a subsidiary thing, deprives it of the opaque externality of an object. The meaningful use of a word, which causes it to loose its bodily character, makes us look through the word at its meaning.
The fact that we can possess knowledge that is unspoken is of course a commonplace and so is the fact that we must know something yet unspoken before we can express it in words. It has been taken for granted in the philosophical analysis of language in earlier centuries, but modern positivism has tried to ignore it, on the grounds that tacit knowledge was not accessible to objective observation. The present theory of meaning assigns a firm place to the inarticulate meaning of experience and shows that it is the foundation of all explicit meaning. [...] We see here how heavily the course of scientific inquiry may rest on deciding whether certain should be taken to be significant or be set aside as accidental.
An unintelligible text referring to an unintelligible matter presents us with a dual problem. Both halves of such a problem jointly guide our minds towards solving them and will in fact be solved jointly by the understanding of the words referred to and the words referring to it. The meaning of the thing and the terms designating them is discovered at the same time.
I have describe the tacit process of understanding experience and that of understanding a report on an experience as two acts of sense-reading. In the process by which a writer picks words for describing his experience, we meet an act of sense-giving.
Our conception of a tree, for example, is formed in a similar way. It arises by the tacit integration of countless experienced of trees and pictures and reports of still others: deciduous and evergreen, straight and crooked, bare and leafy. All these encounters included it forming the conception of a tree; they are all used subsidiary with a bearing on conception of a tree, which is what we mean by the word ’tree’.
Our capacity to endow language with meaning must be recognised as a particular instance of our sense-giving powers.
All knowledge falls into one of these two classes: it is either tacit or rooted in tacit knowledge.
The ideal of a strictly explicit knowledge is indeed self-contadictory; deprived of their tacit coefficients, all spoken words, all formulae, all maps and graphs, are strictly meaningless.
To the question how a child can learn to perform a vast set of complex rules, intelligible only by a handful of experts, we can reply that the striving imagination has the power to implement its aim by the subsidiary practice of ingenious rules of which the subject remains focally ignorant. This king of rule can be acquired tacitly and only tacitly, and it can also be practiced only tactility.
Discovery takes place in two more to less separate stages, an arduous straining of the imagination is followed by a virtually spontaneous appearance of the solution. In his classic study of heuristics, Poincare´ has described cases in which these two phases were sharply separated: the effort of the imagination had ceased for several hours, when the bright idea turned up. Poincare thinks that first a strenuous search loosens possible bits of a solution and that discovery is then achieved by an effortless integration of these bits. He call this integration an illumination; I shall name it intuition.
Both a problem and a suggested solution are in the nature of surmises, but they differ by their degree of explicitness. A suggested solution can usually be clearly communicated and its convincing power be transmitted to others, for its grounds are largely tangible. By a contrast, a problem or any kind of surmise arising in the course of an inquiry — is difficult to explain to others, let alone make convincing to others, for its grounds are mainly unspecifiable.