In both science and Christianity, truth or knowledge comes from
1. Faith. Faith, or the appeal to authority, is considered by most modern analysts to be weaker than other forms of proof, yet it is (a) the source of most knowledge we have and (b) the source of the plausibility structure by which we evaluate empirical data and judge whether to accept or reject new claims to truth. One of the tests of truth is coherence (agreement with other propositions held to be true). As Curtis McDougall notes in his book Hoaxes, "People reject what does not square with previously conceived ideas." Thus, truth in conflict with accepted ideas (whether Phlogiston or logical empiricism) faces an enormous amount of opposition from the inertia of belief.
The tendency of previously erected plausibility structures to guide interpretation and judgment is so strong that conclusions often precede reasoning rather than follow it. In their book The New Rhetoric Chaim Perelman and Lucie Olbrechts-Tyteca note:
It is a common . . . occurrence even for a magistrate who knows the law to formulate his judgment in two steps: the conclusions are first inspired by what conforms most closely with his sense of justice, the technical motivation being added on later. . . . Strictly legal reasons are adduced only for the purpose of justifying the decision to another audience. . . . Fresh arguments, brought in after the decision, may consist of the insertion of the conclusion into a technical framework. . . . (43)The same is true with scientific theories, where theory influences observation and world view influences theory. Technical, conscious, deliberate reasons often follow conclusions generated from one's "sense of science" or "sense of the world" or as Perelman says, an "incommunicable intuition" (44).
Every book making a claim to be non-fiction is an appeal to faith or authority, with an implied "Trust me" on the part of the author. Authors, especially of text books, do not expect their assertions to be empirically tested before being accepted. We have time and resources to make very few direct tests of truth claims, even for simple empirical ones, such as that the Eiffel Tower exists.
2. Values. As Perelman says, "Values enter at some stage or other into every argument" (75), and a priori claims, such as the reality of the external world, the existence of cause and effect, the belief that there is a material explanation for all phenomena, that mind and brain are one (monism) rather than two (dualism)--all these are values-based and not subject to proof.
Values shape perceptions and the selection of data. The selection of data may constitute an argument in itself. (Cf. Charles Darwin, "Let theory guide your observations" [Letters]. (Compare the obvious implications built in to some "news" articles, where selection of details points strongly toward a particular conclusion.)
Note the saying, "What you see depends on where you stand."
3. Testing appearances by one's sense of reality. Facts do not speak for themselves, but must be interpreted through what one believes about reality. Perelman notes:
Normally, reality is perceived through appearances that are taken as signs referring to it. When, however, appearances are incompatible--an oar in water looks broken but feels straight to the touch--it must be admitted, if one is to have a coherent picture of reality, that some appearances are illusory and may lead to error regarding the real. Because the status of appearance is equivocal, one is forced to distinguish between those appearances that correspond with reality and those that are only illusory. The distinction will depend on a conception of reality that can serve as a criterion for judging appearances. Whatever is conformable to this conception of the real will be given value; whatever is opposed to it will be denied value. . . . Every ontology, or theory about the nature of being, makes use of this philosophical process that gives value to certain aspects of reality and denies it to others according to dissociations that it justifies by developing a particular conception of reality. (Article, "The New Rhetoric" 804)The correspondence test of truth is used by everyone. The standard to which the proposition in question must correspond differs in different ontologies or world views.
4. Inference. All those who come to know must do so through inferences--the making of inductive leaps of unknown magnitude. William D. Romey, in "Science as Fiction or Nonfiction? A Physical Scientist's View from a General Semantics Perspective," Et Cetera, 37(3), Fall, 1980, says:
Virtually all science is based in significant ways on inference. Even deductive science has inference at its base in that the principles from which deduction ensues are themselves inferential to begin with. Inference, by its very definition . . . involves the leap across a gap of unknown dimensions to a conclusion. Some inferences may seem at first inevitable and backed up by 'adequate' support. In fact, uncertainty remains an element of even the 'solidest' influences. The structure of nuclear physics is based on inferences developed from what could only be described as fights of fantasy. Molecular biology, genetics, and evolution are based on the same marshy ground. When, in geology books and technical articles, we find details of what happened in a past long before the human species even existed for periods in which only the most remote and fragmentary evidence exists, we know we are in a land very close to the land of fiction. (205)And Dario Fernandez-Morera, in an article, "Materialist Discourse in Academia During the Age of Late Marxism," in Academic Questions 4(2), Spring, 1991, notes that academics are often guilty of presenting unprovable ideas as facts, and "often blur the distinction between the factual and the hypothetical, the real and the imaginary; and they tend to remain in the world of fiction when they ought to have returned to the world of reality" (25).
5. Truths are postulated as universally true but not universally believed. It is not necessary for everyone to agree on moral or religious (or even aesthetic) truth any more than it is necessary for everyone to agree on scientific truth before it is to be rationally acceptable. Many scientific explanations are in dispute, including the Big Bang, continental drift, global warming, the geological column, etc.
6. Objectivity. Science and Christianity are both objective, in that they both posit external standards for the evaluation of new truth claims. Both are open to the charge of subjectivity if their practitioners use personal, internal standards for interpreting the truth claims. The check against such subjectivity is the community (of scientists or Christians). If the whole community is biased or has adopted communally subjective values, its claims will no longer be objective.
Afterword on Science:
The original meaning of "science" was "knowledge," so that "a scientific explanation" was as Arnold Lunn says in The Revolt Against Reason, "an explanation which is in accord with all the known facts" (105). However, "science" has been redefined to mean "knowledge of the material world as explained by reference to the material world" thus, by definition, eliminating knowledge of non-material entities and truths and prohibiting supernatural explanations. Thus, if the truth is that God has created the natural world, then the truth--that is, the real, actual explanation--is by definition "unscientific." Such a definition of science is therefore question begging.