Start by pinning the word down, because most of the muddle around serendipity comes from using it for two different things. I do not mean luck in general, nor a pleasant surprise of any kind. I mean specifically the case where what you find is genuinely valuable and was not the thing you set out to find. The not-searched-for clause is load-bearing: it’s what separates serendipity from competence.
If you didn’t search for a thing, then by definition no directed process delivered it to you — you came across it. I’m treating “encounter” broadly: a tangent in a footnote, a stranger’s offhand remark, a wrong turn. But the structural point is narrow and, I think, hard to deny: unsearched findings have exactly one delivery mechanism, and it is collision, not pursuit.
This is the axiom doing the real work. The more — and the more varied — the material passing in front of you, the more collisions occur per unit time. A monoculture of inputs produces few surprises because everything rhymes; a wide, mongrel diet of inputs produces many. This is why the most serendipity-prone people are usually the ones with suspiciously broad reading habits.
The claim I actually want: you can farm serendipity. Not aim at a particular discovery — that’s ruled out by definition — but reliably increase how much of it happens to you.
The derivation is almost mechanical once the axioms are granted. You cannot choose the finding (D1 forbids it). But you can choose your exposure, and exposure is the input that A2 says drives encounter rate, and A1 says encounter is the sole channel for unsearched findings. So the one lever you control — exposure — is precisely the lever on the quantity of serendipity. You move the supply without touching the content.
Which dissolves the apparent paradox in the name. “Planned serendipity” sounds like “scheduled spontaneity,” but it isn’t, because the plan and the serendipity attach to different objects: the plan governs the conditions (what you read, who you talk to, how much you wander), and the serendipity lives in the outcome, which stays genuinely unplanned. You rig the board; the dice are still dice.