From The God Who is There - end of chapter 2
God has created a real, external world. It is not an extension of His (sic) essence. That real, external world exists. God has also created man as a real, personal being, and he possesses a "mannishness" from which he can never escape. On the basis of their own world-view often these experience-seekers are neither sure the external world is there, nor that man as man is there. But I have come to the conclusion that despite their intellectual doubts, many of them *have had* a true experience of the reality of the external world that exists, and/or the "mannishness" that exists. They can do this precisely because this is how God has made man, in His own image, able to experience the real world and man's "mannishness." Thus they have hit upon something which exists, and it is neither nothing, nor is it God. We might sum up this third alternative by saying that when they experience the "redness" of the rose, they are having the experience of the external world, as is the farmer who plows (sic) his field. They are both touching the world that is.
The days of Genesis 1 (which Schaeffer claims in his Genesis in Time and Space, are unimportant) underscore the external objective reality of the cosmos and our experience of it and within it.
God speaks and rationally related events follow that are congruent with the propositional word. Each event, and the events as a set are separate from God, but also real.
We can experience the reality as it is mediated in the 'days' -- the space-time -- of our normal experience of life in the objective world. The days of action overlap with our days of experience of the results of the communicative action by God and place our experience in the same domain as which God is active in creating.
Yet our experience is also subjectively but genuinely substantiated as we are real persons with objective existence in the objective created world separate from God: it is a world in which we can really know real things and represent them in meaningful propositions (created by word on God's part, understood by word on our part: this provides the basis for empirical inquiry of the created world).
We are linked to the external world and its objectivity by God's communication to us of 'imageness' which gives us genuine 'mannishness', to use Schaeffer's term, and real experience of the real external world. The link is grounded by the days of genesian action that place it objectively in the same days our history is denominated by, and separate it from God, while showing God is active, present and communicative in that domain by which his domain overlaps our domain he thus created by his word.