Non-obviousness as a requirement for patenting.

To be patented, an invention must be new, non-obvious, and useful. New and useful are easy to understand, but non-obviousness is tricky. It's not necessarily what you think it is and it goes beyond simple intuition, and requires examining whether the invention would have been an obvious solution to a person with ordinary skill in the relevant field, considering existing knowledge at the time of invention.

Why didn't I think of that?

For decades, luggage was designed to be carried. Or, depending on the traveler, laboriously lugged. Then Bernard Sadow introduced the first commercial wheeled suitcase in 1970, which was essentially a traditional suitcase with wheels and a strap attached, pulled behind the traveler like a dog on a leash...a dog that often tipped over. It took seventeen years for Robert Plath to design the version we have today, where the bag is on two wheels and pulled with a telescoping handle. That change transformed wheeled luggage from a novelty into an obvious solution, illustrating how many innovations seem inevitable only after someone finally gets the details right.

Of course that's what obvious means

Normally, when we say “obvious,” we're talking about something so straightforward that it requires little explanation once revealed. "Of course, wheeled suitcases would be awesome." This intuitive understanding isn't exactly what we mean in patent law. I can't think of an invention that has crossed my desk which I didn't think was obvious once I understood it. However, in patent-ese, an invention is not considered obvious just because it appears logical in hindsight. Instead, obviousness is evaluated under a structured legal framework. In the United States, the governing analysis arises from Graham v. John Deere Co., which requires consideration of (1) the scope and content of the prior art, (2) the differences between the prior art and the claimed invention, (3) the level of ordinary skill in the pertinent art, and (4) any objective indicia of non-obviousness, such as commercial success, long-felt but unresolved need, or failure of others. The ultimate question is whether, at the time of the invention, the claimed subject matter as a whole would have been obvious to a person having ordinary skill in the art in view of the prior art.

Because patent law rejects hindsight reasoning, reliance on common sense alone can be detrimental for both inventors and those seeking to challenge a patent. Inventors may incorrectly assume that an invention is too simple to merit protection, and competitors often think an invention is obvious because it seems like a natural next step. Patent obviousness requires some specific teaching, suggestion, or motivation that would have led a person familiar with the relevant field to create the invention with a reasonable expectation of success. This legal framework highlights that obviousness is not measured against the general public, but against a version of the most important person in all of the law, the imaginary "reasonable person." Like medical malpractice will often talk of a "reasonable physician in that situation," or like how someone who's not the brightest bulb in the knife drawer can't escape liability for building a haystack that catches fire if he built the haystack in a way that promoted spontaneous igniting because a "reasonable person" who is presumably smarter, would have built it differently. That example sounded better in my head.

PHOSA-what?

The "reasonable person" we're usually talking about in patent law is a person having ordinary skill in the art (PHOSITA). That acronym just rolls off the tongue, doesn't it?  A PHOSITA is an imaginary person who possesses ordinary technical knowledge, routine problem-solving ability, and familiarity with the relevant prior art, but not the creativity or insight of an inventor. The PHOSITA isn't a layperson, who may lack the technical background to appreciate the challenges addressed by an invention, but also isn't a highly advanced visionary genius whose might make every invention appear inevitable. Instead, the PHOSITA is assumed to understand the prior art and recognize when references could reasonably be combined, if there exists a teaching, suggestion, or motivation to do so. This concept reflects the principle that obviousness cannot be established just by showing each element existed independently in the prior art. The question is whether there is a reason for a PHOSITA to combine the elements and have a reasonable expectation of success.

Consider a prior art reference that teaches a peanut-butter-and-jelly sandwich and explains that jelly works particularly well because its sweetness and acidity cuts through the fattiness of the peanut butter. That disclosure provides more than a mere listing of ingredients—it identifies a functional relationship between components. From the standpoint of a PHOSITA, the teaching is not limited strictly to jelly itself, but to the broader concept that a contrasting ingredient with acidity or sharpness can go well with peanut butter. If other prior art teaches that pickles provide acidity and are commonly used to cut through rich or fatty foods, there may be a teaching, suggestion, or motivation to substitute pickles for jelly to achieve a similar balancing effect. In that circumstance, an argument could be made that a peanut-butter-and-pickle sandwich is obvious because the prior art supplies a reason to make the substitution and the result would have been reasonably predictable.

Peanut butter and pickle sandwiches are delicious, BTW.

By contrast, if the prior art merely disclosed PB&J as a recipe without explaining why the combination works, and there were no teachings suggesting that acidic or brined foods pair well with peanut butter, the rationale for combining peanut butter with pickles would be weaker. The analysis does't depend on the combination being unusual or even unappetizing to a layperson, but on whether the prior art provides a reasoned pathway that would have led a PHOSITA to make the combination.

SCOTUS contributes a little chaos

SCOTUS loosened up the test for obviousness in KSR Int’l Co. v. Teleflex Inc. Gone, like my innocence, was the rigid, mechanistic requirement of finding something in the art that provided some teaching, suggestion, or motivation to combine references; in like whatever the opposite of innocence is,  was something more flexible and ill-defined. If the old test was John Lithgow in Footloose, the new test was John Lithgow in Dexter. Now, obviousness is flexible and grounded in real-world problem solving, allowing consideration of the background knowledge and ordinary creativity of the PHOSITA rather than limiting the inquiry to explicit written instructions in prior references.

We don't need to find a reference saying pickles go well with fatty foods. It's enough to have visited a diner once. 

So now, the question is not whether the prior art expressly told the PHOSITA to make the combination, but whether the combination would have been an ordinary and predictable step. Leaving us to argue that the shift from jelly to pickles was not a routine step in the field of sandwiches, and the looks I've received when eating a PB&P suggest that's the case.

That's not the only argument to make, but I'm losing interest in this post, so I'll say something about the Deere factors another time.

So what?

In patent-speak, 'obvious' doesn't mean the same as it does in the outside world. Many innovations seem obvious in hindsight. Don't get caught in that trap, because that's what it is, a trap. A trap that can keep you from patenting your invention and, hopefully, turning that into money. If you ever find yourself thinking about your innovation and hear a voice saying something similar to "of course pickles are great with peanut butter, any idiot should have known that," or "this is too easy a solution, someone else must have thought of it already." Take a step back. Maybe there's a reason you've never seen your product on the market, and maybe that reason is that you're the first to think of it.

Conclusion

Obviousness is an annoying complicated topic in patent law, way more annoyingly complicated than you might think. If you jump to conclusions about whether your invention is obvious, you might be jumping over some valuable intellectual property.