Theories of evolution must provide for the creative acts which brought such theories into existence.

So long as we use a certain language, all questions that we can ask will have to be formulated in it and will thereby confirm the theory of the universe which is implied in the vocabulary and structure of the language.

Of course language manifests a belief only if we use its words with the implied acceptance of their appositeness.

We cannot ultimately specify the grounds (either metaphysical or logical or empirical) upon which we hold that our knowledge is true. Being committed to such grounds, dwelling in them, we are projecting ourselves to what we believe to be true from or through these grounds. We cannot therefore see what they are. We cannot look at them because we are looking with them.

While tacit knowledge can be possessed by itself, explicit knowledge must rely on being tacitly understood and applied. Hence all knowledge is either tacit or rooted in tacit knowledge. A wholly explicit knowledge is unthinkable.

Admittedly, scientific authority is not distributed evenly throughout the body of scientists; some distinguished members of the profession predominate over others of a more junior standing.

I shall suggest, on the contrary, that all communication relies, to a noticeable extent on evoking knowledge that we cannot tell, and that all our knowledge of mental processes, like feelings or conscious intellectual activities, is based on a knowledge which we cannot tell.