Human existence depends upon the observation and comprehension of natural rules. The search for objective natural rules is the search to define lawlike generalizations that govern the natural world. However, the human understanding and experience of nature is bound by human consciousness, and in particular by human language. As the process by which we come to know laws is largely linguistic, human knowledge is characterized by conjecture. As a result, when observing nature, humans are subject to the formation of accidentally true generalizations. Because laws are essential to life, we must learn to distinguish lawlike generalizations from accidentally true generalizations, in order to learn which conjectures are valid and which conjectures should be disregarded.
In order to explain the role of laws, this paper will examine the definition and use of the word law, describe how it is that we come to know laws, and distinguish between lawlike generalizations and accidentally true generalizations.
What is a Law?
The philosophical examination of science distinguishes between two distinct uses for the word 'law': as a natural referent and as a linguistic entity.
When used as a natural referent, the term 'law' refers to a thing that exists in the natural world. A natural law is something that humans must endeavor to detect and understand. The significant characteristic of natural laws is that they exist independently of humans and human consciousness; natural laws exist whether humans perceive them or not. This may be seen by appealing to Darwin's theory of evolution: humans have not always existed, humans evolved from primal forms of life, thus nature existed prior to humans, thus the laws of nature existed prior to humans, and thus the existence of the laws of nature is independent of the existence of humans.
The importance of the distinction made above becomes clear when considering the second usage of the word law, which is as a linguistic entity. In this second usage of the word 'law,' the term refers to the statement of a natural law as expressed in and contained by human language and human consciousness. The origin of the linguistic entity 'law' is determined by examining nature itself: existence. Where do humans exist? In nature. How do humans operate in nature? By applying knowledge of nature. What knowledge do humans possess? In the case of natural laws we are concerned with a posteriori knowledge, knowledge defined as that based upon experience of the natural world. The formal effort to understand and express a posteriori knowledge is science: the discovery and explication of natural laws. Hence, a linguistic 'law' entity is a human invention that refers to a natural 'law' referent.
When separating the word 'law' into its component meanings it is clear that natural laws exist and operate independently of humans, and that humans must discover and understand laws through experience of the natural world. The question then arises: how is it that laws are discovered and understood? What is the methodology of the natural sciences (as distinguished from the a priori sciences, such as pure mathematics)? Looking to patterns in the history of science we see that the discovery of a law begins with the generalization of a proposition over the observed instances of some natural phenomena. We "argue from several particular cases to the truth of a generalization covering them." To construct such a generalization is to make a prediction based upon past experience. This form of reasoning is known as inductive inference, or induction. The force of inductive prediction is that it is ampliative; information in the conclusion of an inductive argument goes beyond the information in the premises, and thus an inductive inference increases our knowledge of the natural world.
Though induction adds to our empirical knowledge and enables predictive generalization, the history of science shows that not all generalizations are equally valuable. Scientific theories and explanations are constantly being revised and even discarded in light of improved theories and new information. How can a valuable generalization be distinguished from a valueless generalization?
Lawlike Generalizations and Accidentally True Generalizations
In attempting to resolve whether a generalization is valuable or valueless, we find "the difference is that in the former case the hypothesis is a lawlike statement; while in the latter case, the hypothesis is a merely contingent or accidental generality."
An accidentally true generalization occurs when a true statement is made regarding some natural fact, but the natural fact in question is not the result of a natural law. The existence of the regularity in question is coincidental, and there is no natural law governing the phenomenon or relation. Because accidentally true generalizations do not express a state that is based on natural laws, they do not support counterfactuals. Accidentally true generalizations are unable to tell us anything meaningful about the natural world. One example of an accidentally true generalization would be the observation that "there are no houses in Canada that are one million square feet," which might be the case, but is unable to support counterfactuals, as there are no natural laws prohibiting the construction of such a house.
A lawlike generalization occurs when a true statement is made regarding some natural fact, and the natural fact in question is the result of a natural law. The linguistic statement of the general principle has been abstracted from the observed phenomena, and is able to receive confirmation from its physical instances. One example of a lawlike generalization would be Einstein's theory of relativity.
The Role of Laws
Having determined the metaphysical status of the natural referent 'law,' knowing the origin of the linguistic entity 'law,' and understanding the difference between valuable lawlike generalizations and valueless accidentally true generalizations, it is now possible to articulate the role of laws. The linguistic conception of a law is used to explain the instances of some natural phenomenon; laws define objective relationships, and provide explanations of the relationships between natural kinds. It is for these reasons that an accidentally true generalization can never play the same role as a lawlike generalization. Accidentally true generalizations are not capable of receiving confirmation from an instance, and can never provide an explanation.
The fact that laws are fundamental to natural existence may be seen by considering the case of humanity. The apprehension of natural laws enables humans to operate in the world. If natural laws did not exist then the natural world would lack natural order, and this would be replaced by disorder. A disordered environment with no natural laws would not permit the construction of explanation, and humans would have no basis for understanding the world, and would consequently be rendered unable to interact with the world. Indeed, in the absence of laws the world might not exist, as it may not be possible for kinds to exist without laws.
Natural laws exist outside of human cognition, and underpin the natural order of the universe, acting as a foundation for natural explanations relating natural kinds. Nature has developed in humanity the capacity to experience and discover laws through inductive generalizations, but because of the peculiarities of the inductive reasoning process there exists the possibility that our generalizations regarding nature may be false or accidentally true. By understanding the role of laws we may detect those generalizations that are accidentally true, and instead place our efforts towards the application, refinement, and extension of lawlike generalizations.
Part of the series: UWO