"It is the theory that decides what we can observe." (Einstein)
"It is more important that a theory be beautiful than it be true." (Paul Dirac)
In Greek, theoria originally meant a looking at or viewing and theoreo, a spectator. In this sense, theory and Visuality are metaphors of each other.
Is the theoretical attitude is that of the disengaged observer? Does theory require a distinction between the illusionless observer and the gullible participant, or to put it more mildly, between theory and observation? Does theory always entail what John Dewey derided as the "spectator theory of knowledge"? Perhaps to theorize is to create the impression of something that existed already (or, even better, always already) (see metaphor) In the Pragmatic tradition, theory is the critical reflection on "belief." William James calls it "an appetite of the mind," what Frank Lentricchia calls "the need to generalize" and "to obliterate differences." (quoted in Cary Wolfe, Postmodern Theory and the Pragmatics of the "Outside" )
But according to the Greek conception, theory is not a knowledge but touching (thigein ).
Darwin often remarked that no man could be a good observer unless he was an active theorizer as well.
"...We could say that creating a new theory is not like destroying an old barn and erecting a skyscraper in its place. It is rather like climbing a mountain, gaining new and wider views, discovering unexpected connections...But the point from which we started out still exists and can be seen, although it appears smaller and forms a tiny part of our broad view gained by the mastery of the obstacles on our adventurous way up." (Einstein) (cf fitness landscape) One difference between science and critical theory is probably that this metaphor of climbing to greater heights is not so persuasive to cultural critics.
In his partly autobiographical Thought in Medecine, Helmholtz contrasts the slow and painful climb of the adventurous thinker with the "royal road" that appears to him once he reaches the top. Helmholz described his publications as taking his readers along the royal road, which bears no ressemblence to the crooked and tortuous path he created for himself. (cf. "royal science" vs "nomad science" for D+G in eg. form / matter ) The concept of the "royal road" refers to Euclid. According to Proclus' Commentary on the first book of Euclid's elements, Ptolemy I, king of Egypt once asked Euclid for a shorter way to mastering geometry than working through the Elements. Euclid answered, "There is no royal road to geometry."
What are the spaces of possiblity for theories?
Under a general hypothetico-deductive view of theories, as formalized by the heirs of logical positivism, a theory is understood as offering hypotheses from which, in combination with empirical assumptions, deductions can be made regarding empirical results. For a theory to be considered a complete or adequate theory about the natural world, some or all of these hypotheses must purport to be "laws of nature." Laws are usually explicated as strictly universal statements incorporating some sort of physical necessity. Thus, at the heart of scientific theories are models or representations that describe a mechanism by which a cause, be it event or state or potent thing or substance, brings about the effect, event, or state. (Elizabeth Lloyd, Rom Harr ) (see explain / describe)
What is the relation between theory and experiment? Most philosophers of science stress that experiment takes place within a framework of questions established by theory. Karl Popper, for example, claims that "The theoretician must long before have done his work, or at least the most important part of his work: he must have formulated his questions as sharply as possible. thus it is he who shows the experimenter the way." (The Logic of Scientific Discovery, p. 107) In Representing and Intervening, Ian Hacking points to a number of counterexamples to this relationship, in optics, for example, where significant observations as well as experiments preceded any theory. While he does not claim that experimental work could exist independent of theory, (what Bacon referred to as the blind work of "mere empirics") Hacking points to examples where truly fundamental research can precede any relevant theory whatsoever.