Unicorns, PHOSITAs, and Other Creatures

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The “reasonable man” or “reasonable person” is that mythical creature (not unlike a unicorn) that exists in many different areas of law purportedly to allow us to view the situation at issue from a reasoned, logical, objective perspective. We have in patent law a special breed of this legendary beast – the “person having ordinary skill in the art” or PHOSITA. In teaching students about the PHOSITA, I had always assumed that the concept would be fairly simple to grasp, since the reasonable person was, or at least should be, familiar to them. This assumption was shattered, indirectly, by one student’s exam answer.

I am not sure if the student was absent the day I introduced the PHOSITA and thus he took me at my phonetic pronunciation, or if instead he was clever and was making a point I had earlier failed to grasp. (I personally believe the former, but I could be wrong.) Anyway, he answered all of his exam questions by looking at the issue from the perspective of the “Faux-Cita.” The fairy-tale beast raises its ugly head…


For me, any amusement during exam grading results in an unnatural amount of laughter. But once I recovered from this outburst, I started thinking about the unintended wisdom of the “faux-cita”. This reasonable person, or ordinary artisan, is a concept that I took for granted; but in reality, this legal fiction is a moving target for students. He changes based on the invention in question – the PHOSITA in rocket science is different from the PHOSITA in running shoes. But he also may change based on the test for which we are using him – How would a PHOSITA understand this claim term? Would a PHOSITA understand how to make & use the invention based on this disclosure? Would a PHOSITA have found this invention obvious?

The question for me is how to trap this fantastic being and make him real for my students. How do you explain a legal fiction without exposing that there is no Tooth Fairy? Once the word “fiction” comes out, students understand that this is something we have “made up” and therefore presume it is not meaningful. Even if they can get over that the most important person at the table is not real, they still do not know how he factors into the equation – especially since we don’t know who he is (and in patent law, he is likely to be unlike any of us). So how do you bring your legal fiction into reality?

(Image Source: The Lady and the Unicorn, Wikicommons)

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5 Responses

  1. See also: Douglas Hofstadter’s myriad writings on counterfactuals and logic. How can a subjunctive assertion starting, “If I were you …” have any meaning? Clearly I’m not you, so anything asserted in such a subjunctive is “fictional”, and has no meaning in the real world.

    Maybe law students would benefit from some background in mathematics or physics, where at every turn we use such fictions as “test particles” which have the magical ability to measure the electric field without contributing any field of their own. And yet somehow we manage to make rigorous, testable predictions and show that there’s a meaning to an idealization like the PHOSITA after all.

  2. Chris says:

    What we need are philosophers, who generally gloss “if p were the case, then q” as “in the closest possible world where p is the case, q is also the case.” See, e.g., here.

  3. JP says:

    I understand that law professors abhor this, but I would suggest explaining a practical application.

    Encountering the Reasonable Person in law school, it seemed like a kind of pointless rhetorical device. In civil litigation however, I learned it’s actually a fairly useful rhetorical device. When the Reasonable Person pops up as an issue, I focus my writing on conveying that I am the Reasonable Person–and the Judge can be too, if only she accepts my arguments, and not those of opposing counsel and his client.

    I would think something similar could be done for the PHOSITA. That is, pick out someone on your side (your client, your client’s employee, your expert), and convince the Court that that person is PHOSITA. Rather than a “moving target,” PHOSITA becomes a flexible and practical tool. (I would love to know if any patent lawyers have thoughts on this).

    Of course, if any students ask how judges use the Reasonable Person and PHOSITA, you can just explain the truth: it’s a way to avoid saying “Well, it seems to me that ….”

  4. TGP says:

    As a Law Student just encountering the idea of a reasonable person it became pretty clear early on that there is no one reasonable person in an objective sense. In my mind i think of it along the lines that JP does. The reasonable person is me and the people i can get to agree with me. It has come down to, “well ya that makes sense to me” or an “i could see that”. Reasonable becomes an agreement on a norm built originally from my own view.

  5. pl says:

    That is, pick out someone on your side (your client, your client’s employee, your expert), and convince the Court that that person is PHOSITA. Rather than a “moving target,” PHOSITA becomes a flexible and practical tool. (I would love to know if any patent lawyers have thoughts on this)

    JP, patent lawyers do this all of the time, though perhaps not quite as far as it sounds like you take it.

    Sometimes people on the other side are PHOSITAs too, when they make damaging admissions.