The discussion thread to vjtorley’s excellent post below veered off on the issue of the nature of “Truth.” The issue is: Does science say anything that is “True” with a capital “T”? That is to say, does science make absolute statements? That is an issue that deserves its own post.
To answer this question, we must answer some preliminary questions first. The most basic question is this: What does it mean for a statement to be “true”? Here Kairosfocus quotes Aristotle: “to say of what is, that it is, and of what is not, that it is not, is true.” (Metaphysics 1011b). Just so. This is the classic formulation of the “correspondence theory of truth.” True statements are those statements that correspond with the actual state of reality.
Consider Bertrand Russell’s famous cat on a mat. Russell used the statement “The cat is on the mat” to explain the issue of correspondence. That statement is true if there is a cat and if there is a mat and if the cat is related to the mat by being on it. Before going further we must first recognize that the meaning of an English sentence is based upon the conventions of English grammar and the commonly understood meanings of the words employed, which are in turn conferred by how the words are generally used in the community of speakers. As Wittgenstein said, “Meaning is usage.”
With this in mind we find that the grammar of the sentence is in a very simple subject (the cat); predicate (is on); object (the mat) format. As English speakers when we hear this sentence we naturally understand the usage of the terms used. We think of a domestic cat (Felis catus) laying on a rectangular piece of protective fabric in such a way that its body is mostly on that mat. And if we look across the room and see that our tabby Felix the Cat is stretched out on the doormat so that his body is all but covering it, we say the statement is true.
Here is the important thing to take away from this simple example. When I say “The cat is on the mat,” and Felix is in fact stretched out on the doormat at the moment I am speaking, the statement is true in an absolute sense. It is true for you; it is true for me; it is true at all times and places and under all conditions that at this time and place “The cat is on that mat.”
Now to the analysis of vjtorley’s question. He asks whether the statement “The Sun is a G2V star” is a statement that is true in an absolute sense. Let’s break it down.
Grammar: Again, the grammar is simple and unmistakable: Subject (the Sun); predicate (is); object (a G2V star).
Let’s go to the words. Allan MacNeill suggests that “The Sun” is not the English word for the star at the center of our solar system. This is not correct. When English speakers are talking about the star at the center of our solar system they almost always use the words “the Sun.” For example, the Wikki article on the Sun starts with the following sentence: “The Sun is the star at the center of the Solar System.” It is true that our sun one of many “suns” and therefore vjtorley’s language is not as precise as it could be. Nevertheless, there cannot be the slightest doubt that the phrase “The sun” in our sentence means the star at the center of our solar system.
The predicate here (“is”) means “to exist in a state of being.” In other words, the sentence means the sun exists in the state of being a G2V star.
Finally, according to Wikki, the phrase “G2V star” is a spectral class label. G2 indicates the sun’s surface temperature is approximately 5500C, and V indicates that the sun is a main sequence star and thus generates its energy by nuclear fusion of hydrogen nuclei into helium.
Let us now combine all of these factors together. We find that
(1) if there is a star at the center of our solar system named the sun; and
(2) if that star exists in a state of being a G2V star where G2V star means a main sequence star with a surface temperature of 5500C;
then the statement is true. Each of these variables (sometimes called “truth conditions”) has been investigated and we find that they all exist. Therefore, we can say that the English sentence “The Sun is a G2V star” is true in an absolute sense of the word.
Hold the presses! Isn’t it a commonplace among scientists that science does not make “absolute statements”? Indeed it is. Popper put it this way:
Science does not rest on solid bedrock. The bold structure of its theories rises, as it were, above a swamp. It is like a building erected on piles. The piles are driven down from above into the swamp, but not down to any natural or given base; and if we stop driving the piles deeper, it is not because we have reached firm ground. We simply stop when we are satisfied that the piles are firm enough to carry the structure, at least for the time being.
Karl Popper, The Logic of Scientific Discovery, (New York, Routledge Classics, 1959, reprint of first English edition, 2002), 94.
Popper means that all scientific statements are contingent and tentative, and this is certainly true. Dr. MacNeill, if I understand him, has been making this point, and I agree with him.
So what gives? Are all scientific statements contingent and tentative or can some scientific statements be absolute? The answer is that both are true, and the confusion lies in the fact that the phrase “scientific statement” is being used in two different ways.
Instead of “scientific statement,” let us use the phrases “scientific fact” and “scientific theory.” A “scientific fact” is a statement like “The Sun is a G2V star.” As we have seen, if the truth conditions of that sentence are met, as a simple matter of English usage, the statement is true in an absolute sense.
On the other hand, consider the following sentence: “The diversity and complexity of life is the result solely of Neo-Darwinian processes.” The simplicity of this sentence disguises the fact that it is not a simple fact statement like “The Sun is a G2V star.” Instead, it is a summary of the currently dominant theory of origins. It is a synthesis of not one but literally millions of observations and inferences from those observations. Most scientists believe that the sentence is true, but few, if any would say it is true in an absolute sense. Like all scientific theories, it is contingent and tentative, subject to being displaced at any moment were a disaffirming observation to be encountered. Both sides of the ID/NDE debate should always keep in mind that no number of positive observations can “confirm” a scientific theory in the absolute sense; yet is takes only one negative observation to falsify it.