You might be familiar with Arthur C. Clarke’s Third Law, “Any sufficiently advanced technology is indistinguishable from magic.” Clarke tucked this away in a footnote without explanation, but it fits in with the discussion of magic in Chapter III of James Frazer’s magnum opus The Golden Bough. These two works have shaped a lot of my thoughts about science, technology and the way we interact with our world.

Frazer lays out two broad categories of magic, homeopathic magic and contagious magic. Homeopathic magic follows the Law of Similarity, and involves things like creating effigies of people in order to hurt them, and keeping red birds to cure fever. Contagious magic follows the Law of Contact, and involves things like throwing a child’s umbilical cord into water to improve the child’s swimming abilities later in life, or a young woman planting a marigold into dirt taken from a man’s footprint to help his love for her grow.

Frazer is careful to observe that the Laws of Similarity and Contact are widespread cognitive patterns that people use to understand their environments. In semantics we know them as the foundation of the processes of metaphor and metonymy, respectively. He notes that sympathetic magic’s “fundamental conception is identical with that of modern science: underlying the whole system is a faith, implicit but real and firm, in the order and uniformity of nature.”

In this both science and magic stand in contrast to religion: “if religion involves, first, a belief in superhuman beings who rule the world, and second, an attempt to win their favour, it clearly assumes that the course of nature is to some extent elastic or variable, and that we can persuade or induce the mighty beings who control it to deflect, for our benefit, the current of events from the channel in which they would otherwise flow.” After this Frazer engages in some sloppy thinking, concluding that because religion seems to have arisen after magic it must be an improvement over what the “savages” do. He also fails to complete the fourth quadrant of his taxonomy: that as science is to magic, social sciences are to religion.

The key difference between magic and science (and between religion and social science) is the element of faith. The potion brewer doesn’t check to see that there is a logical explanation for the inclusion of certain ingredients. If the potion fails, she must have gotten impure ingredients, or misread the incantation. A scientist looks for explanations as to why a medicine works when it works, and why it fails when it fails.

Some of you may be thinking that Clarke’s quote was about technology, not science. I first learned of technology as “applied science,” which should mean that it’s no more faith-based than science itself. In practice, it is not possible to understand every tool we use. In fact, it’s not even possible for a human to completely understand a single tool, in all its complexity.

My stepfather was a carpenter. When I was first taught to hammer a nail, I started out by picking the hammer up and putting it down on the nail, vertically. I had to be shown how to swing the hammer to take advantage of the angular momentum of the hammer head. It took another layer of learning to know that I could swing from my wrist, elbow or shoulder to customize the force of the hammer blow to the task at hand, and then another to get a sense of the various types of hammers available, not to mention the various types of nails. In a home improvement project several years ago I discovered that, as electric screwdrivers have gotten smaller and lighter, practices have changed and people use screws in situations where nails used to be more common.

My stepfather might at some point have explained to me why his hammer heads were steel and not iron, and the handles were hardwood and not softwood, metal or fiberglass, but his explanations did not go to the molecular level, much less the atomic or quantum levels. To be honest, all I needed to know was “steel is solid, heavy and doesn’t rust” and “hardwood is solid but absorbs some of the impact.” The chance that the molecular or subatomic structure of the hammers would affect our work beyond that was so small that it wasn’t worth spending time on.

At the beginning I didn’t even need to know that much. All I needed to know was that my stepfather had handed me this hammer and these nails, and told me to nail those two boards together at that angle. I had to trust his expertise. As I began to get comfortable, I started asking him questions and trying things slightly different ways. Eventually people get to the point of saying, “Why not a fiberglass handle?” and even “Why not an electric screwdriver?” But at first it’s 99 percent faith-based.

That’s how the technology of hammers and nails and houses works, but the same principles apply to technologies that many people take for granted, like pencils (we know how to sharpen them, but how many of us know how to mine graphite?) and clothing (some of us can darn a sock, and some of us can knit a scarf, but how many of us have even seen any of the machines that produce shoelaces, or Spanx?). We take it on faith that the pencils will write like they’re supposed to, and that socks will keep our feet warm.

This, then, is what Clarke meant when he talked about technology being indistinguishable from magic. Yes, Sprague de Camp portrayed ancient Romans mistaking explosives for magic in his 1939 novel Lest Darkness Fall (which explicitly invokes the sympathetic and contagious forms of magic described by Frazer). And the magically moving photographs described by J.K. Rowling in Harry Potter and the Philosopher’s Stone have become real technology just twenty years later, omnipresent in the UK and the United States.

But beyond the simple resemblance between technology and magic, if someone is not inclined to be critical or scientific, their relationship to technology is functionally the same as it would be to magic. If the technology is sufficiently advanced, people can do the same things they’ve always done. They don’t need to “get under the hood” (now there’s an example of non-magical technology!) because it seems to work most of the time,

On the other hand, our faith is not blind. I had faith in my stepfather to teach me carpentry because my mother and I had lived with him and trusted him, and seen his work. I also learned to have faith in cars to get me places safely, but as I learned more about kinematics and human attention, and as I was confronted with more evidence of the dangers of this technology, I realized that my faith was misplaced and revised my habits.

Our faith in these technologies is based on a web of trust: I trusted my stepfather when he told me that if I hit the nails this way they would securely fasten the pieces of this house together and if properly maintained, it wouldn’t fall down on us. He in turn trusted his training from other carpenters and recommendations from other professionals in related fields, which were then corroborated, revised and extended by his experiences.

I want to stress here that these methods were also supported by scientific studies of materials and manufacturing. Over the millennia, carpenters, architects and other craftspeople have tried using different materials, different structures, different techniques. Some worked better, some didn’t work so well. They’ve taken the materials apart to figure out what makes them strong in some ways and flexible in other ways. This is an ongoing process: vinyl siding may have seemed like a good idea at the time, but it can pollute if burned or discarded.

That is how you tell the difference between technology and magic: every aspect of the technology is open to question and revision. With magic, you may be able to try new things or test the existing methods, but beyond a certain point there is no more trying or testing, there is only faith.