Even the terms contained in natural law statements are vulnerable to attack by the skeptics. Hume argued more than two hundred years ago that we humans can’t really know that any of the laws we think we see in nature are absolutely true because when we state a natural law, the terms we use to name the objects and events we want to focus on exist only in our minds. A simple statement that seems to us to make sense, like the one that says hot objects will cause us pain if we touch them, can’t be trusted. To assume that this “law” is true is to assume that our definitions for the terms hot and pain will continue to make sense in the future as they have in the past. But we can’t know whether these assumptions will hold in the future. We haven’t been to the future.

Thus, all of the terms in natural law statements, even terms like protons, atoms, acids, genes, cells, galaxies, and so on, are fabrications of our minds, terms that we create because they help us to sort and categorize our sensory experiences and memories of sensory experiences and talk to one another about what seems to be going on around us. But reality does not contain things that are somehow qualified naturally as atoms, cells, or galaxies. If you look at a gene, it won’t be wearing a name tag that reads “Gene.” In Somali, it is called “hiddo”. But it still is what it is. 

Right from the start, our natural law statements must gamble on the future validity of our current mental categories—that is, our human-invented terms for things. The terms can seem sound, but they are still gambles, and some terms that humans once gambled on with great confidence turned out later, in the light of new evidence, to be naïve and inadequate.

                          

                                        

                                                                                           Isaac Newton.

Isaac Newton’s laws of motion are now seen by physicists as being useful, low-level approximations of the subtler, relativistic laws of motion formulated by Einstein. The substance called phlogiston once seemed to explain all of chemistry. Then Antoine Lavoisier did some experiments showing phlogiston didn’t exist. On the other hand, people spoke of genes long before microscopes that could reveal them to the human eye were invented, and people still speak of atoms, even though no one has ever seen one. Some terms last because they enable us to build mental models and do experiments that work. But the list of scientific theories that eventually fell from fashion is very long.

                              

                                                         Marie and Antoine Lavoisier