What Kuhn, Derrida, and I believe is that it is pointless to ask whether there really are mountains or whether it is merely convenient for us to talk about mountains. 
There is no activity called ‘knowing’ which has a nature to be discovered . . . there is simply the process of justifying beliefs to audiences. 
[T]he relation between our truth claims and the rest of the world is causal rather than representational. It causes us to hold beliefs, and we hold the beliefs which prove to be reliable guides to getting what we want. If this claim is true of the world, then it represents nothing of the world outside itself, that is to say, it is not true of it; rather it has only been caused by that world. What precisely caused this absurd belief is a matter of conjecture, but how it might prove a reliable guide to getting what we want is a matter of personal exigency, perhaps of the sort that gets one noticed in intellectual circles.
When we say that our ancestors believed, falsely, that the sun went around the earth, and that we believe, truly, that the earth goes round the sun, we are saying that we have a better tool than our ancestors did. . . . The argument between us and our medieval ancestors should not be about which of us has got the universe right. It should be about the point of holding views about the motion of heavenly bodies, the ends to be achieved by the use of certain tools. Confirming the truth of Scripture is one such aim, space travel is another. 
Thus: the belief that the sun goes round the earth is “true” only in the sense that it is useful or convenient for our purposes to believe so; the same goes for all beliefs about the motion of heavenly bodies – or for any belief about anything; for no one has access to a mind-independent reality by which he might test his theories. So accommodating a philosophy – where truth is simply what is useful for our purposes – is a sublime gift to charlatanry, if not tyranny.
To say that one should replace knowledge by hope is to say . . . that one should stop worrying about whether what one believes is well grounded and start worrying about whether one has been imaginative enough to think up interesting alternatives to one’s present beliefs. 
Is this good advice to a man who needs to cross a wooden bridge, after he has just witnessed a friend fall to his death through one of its rotten boards? I suggest that the interesting alternative of jumping up and down on said boards whilst remaining hopeful of support from good fairies would be inferior to the present and well-grounded belief that doing so is likely to end in tragedy – and that one should therefore hold the rails and tread lightly. Perhaps Rorty would find such an example silly. If so, it is incumbent upon him to explain why.
[I]t is not clear that any of the millions of ways of describing the piece of space time occupied by what we call a giraffe is any close to the way things are in themselves than any of the others. . . . all we need to know is whether some competing description might be more useful for some of our purposes. 
Both the words we use and our willingness to affirm certain sentences using those words and not others are the products of fantastically complex causal connections between human organisms and the rest of the universe. There is no way to divide up this web of causal connections so as to compare the relative amount of subjectivity and of objectivity in a given belief. There is no way, as Wittgenstein has said, to come between language and its object, to divide the giraffe in itself from our ways of talking about giraffes. As Hilary Putnam, the leading contemporary pragmatist, has put it: ‘elements of what we call “language” or “mind” penetrate so deeply into reality that the very project of representing ourselves as being “mappers” of something “language-independent” is fatally compromised from the start.’ 
— Professors of philosophy excepted, of course.No organism, human or non-human, is ever more or less in touch with reality than any other organism. 
Looking at language in [a] Darwinian way, as providing tools for coping with objects rather than representations of objects, and as providing different sets of tools for different purposes, obviously makes it hard to be an essentialist. For it becomes hard to take seriously the idea that one description of A can be more ‘objective’ or ‘closer to the intrinsic nature of A’ than another. The relation of tools to what they manipulate is simply a matter of utility for a particular purpose, not of ‘correspondence’. 
[Y]ou should notice that it would be inconsistent with my own antiessentialism to try to convince you that the Darwinian way of thinking of language — and, by extension, the Deweyan, pragmatist way of thinking of truth — is the objectively true way. All I am entitled to say is that it is a useful way, useful for particular purposes. All I can claim to have done here is to offer you a redescription of the relation between human beings and the rest of the universe. Like every other redescription, this one has to be judged on the basis of its utility for a purpose. 
The first is that it makes it impossible to formulate a lot of the traditional philosophical problems. The second is that adopting it makes it easier to come to terms with Darwin. 
The end of the moral interpretation of the world, which no longer has any sanction after it has tried to escape into some beyond leads to nihilism. . . . [T]he untenability of one interpretation of the world, upon which a tremendous amount of energy has been lavished, awakens the suspicion that all interpretations of the world are false. 
I think that ‘relativism’ and ‘postmodernism’ are words which never had any clear sense, and that both should be dropped from our philosophical vocabulary. 
Then there was the thief who thought it useful if everyone deemed the words “theft” and “robbery” to be without any clear sense, that both should be dropped from the vocabulary of criminal justice.
 R. Rorty, “Does academic freedom have philosophical presuppositions?” in Academic Freedom and Tenure: Ethical Issues, ed. R.T. DeGeorge, (Lanham, Maryland: Rowman & Littlefield Publishers, 1997), p.184.
 R. Rorty, “Truth Without Correspondence to Reality”, in Philosophy and Social Hope (London: Penguin Books, 1999), p.36.
 Ibid., p.33.
 Ibid., “Introduction: Relativism: Finding and Making”, p.xxv.
 Ibid., “Truth Without Correspondence to Reality”, p.34.
 Ibid., “Introduction: Relativism: Finding and Making”, p.xxvi.
 Ibid., p.xxvii.
 Ibid., p.xxv.
 Ibid., “ A World Without Substances or Essences”, p.65.
 Ibid., pp.65-6.
 Ibid., p.66.
 F.W. Nietzsche, The Will to Power, tr. W. Kaufmann & R.J. Hollingdale (New York: Vintage Books, 1968), p.7.
 R. Rorty, “Trotsky and the Wild Orchids”, in op. cit., p.8.
 Ibid, Preface, p.xiv.