So how do we know?
How that question is answered will immediately create a small scission between secular and religious conservatives. That scission, however, has consequences in a number of respects.
Knowledge in its most general sense is a relationship between knowers, what is known, and methods of knowing. The latter question has been a long running philosophical controversy.
Although Aristotle never wrote a systematic treatise in the modern sense on epistemology, his primary method of acquiring knowledge in practice was experience. In the natural sciences, Aristotle collected examples of different species of animals and recorded his observations about them. In the social sciences, Aristotle described the constitutions of various city-states that dotted the Mediterranean. Thus, for Aristotle, knowledge began with experience. His works on logic, especially Posterior Analytics, provided guidance on how to correctly reflect upon experience. Together these works were later called the Organon--a tool or method. Such an approach to knowledge is a type of empiricism.
Future posts will try to establish a connection between empiricism and conservatism.
There are, of course, different kinds of experiences. First, people share the everyday experiences of living in our material world. People draw conclusions from these everyday common experiences to help themselves get about. Second, others may engage in systematic recording of their experiences (or those of others) and suggesting some conclusions about those experiences. This constitutes Aristotle's approach to scientific investigation and explains both its successes and its limitations. Finally, modern scientists create specialized or artificial experiences in a laboratory. This allows them to remove variables that complicate the investigations of nature. This is the essence of modern experimental science. These different kinds of experiences lead to different degrees of certitude about conclusions drawn from those experiences.
A general look at the various branches of science illustrates this notion of degrees of certitude. The knowledge contained in the formal sciences of mathematics and logic exhibit the highest degree of certitude and incorrigibility. The conclusions of the physical and biological sciences, largely based upon the specialized experience of the laboratory, possess a lesser degrees of certitude and incorrigibility. These degrees of certitude change with either additional information or better reasoning. Finally, the knowledge claims of the social sciences seem to be the most open revision.
That there are varying degrees of certitude regarding knowledge is not new. The philosophers of the classical world observed that some things were known with more certitude that others. Consequently, they drew a distinction between what they called knowledge (episteme) and what they called informed opinion (doxa). The former term referred to beliefs that commanded such certitude that they were beyond a reasonable doubt. The latter term referred to beliefs about which they had varying degrees of certitude. Unfortunately, modern philosophy seems to have lost this acceptance of limitations. It has raised all sorts of perplexing and insoluble questions as it embarked on a futile search for certainty.
When someone makes a knowledge claim, they assert that they in some sense possess the truth. The idea of truth has been debated about as much as the question of knowledge. So what is truth? Aristotle provided a minimalist definition that “To say of what is that it is not, or of what is not that it is, is false, while to say of what is that it is, and of what is not that it is not, is true” Thomas Aquinas, the most well known interpreter of Aristotle, gave a little more robust definition in his assertion that “A judgment is said to be true when it conforms to the external reality.” This has come to be known as the correspondence theory of truth. This endures as the best and most common sense understanding of the idea of truth. As the definition of Aquinas implies, this concerns knowledge claims about external, material reality. It does not fit with logical truths of mathematics. More controversially, neither does it pertain to the notion of moral truths.
Christians accept all of the above claims. In fact, many of the most important scientists of the past (and perhaps today) professed some variety of Christianity. But Christians (as well as devotees of other religions) add something else. Christians claim that a supernatural being exists who has provided additional knowledge not accessible through experience. They claim that this being communicated through sundry means with select individuals: "We interrupt this cognitive apprehension of reality with a message from Almighty God." And these individuals wrote down the contents of these communication in a collection of writings known as the Bible. As might be expected, Christians disagree about whether or not this communication continues today.
If the Bible confined itself to spiritual matters--those things that the Bible says "pertain unto life and godliness through the knowledge of him that hath called us to glory and virtue"--the claim of divine communication would be extraordinary enough but of little interest beyond those spiritual matters to those who believe. The Bible, however, makes additional knowledge claims about the natural world, human history, and the future of them both.
And those claims are problematic when it comes to considering the Bible is a source for truth: we can confirm or disprove such knowledge claims about our universe by means of the sciences.
We cannot confirm, however, that a immaterial dimension exists which is inhabited by a supernatural being.
We cannot confirm the existence of such a supernatural being.
We cannot confirm that this alleged supernatural being has communicated with mankind.
Such knowledge claims elude any method of knowing, whether observation, experimentation, or mathematical calculation. Beliefs in such claims rest only upon the psychological disposition of one who believes--his faith.