The four-axis ranking
We rank humanity’s most important problems on four quantifiable dimensions — quantity of humans affected, severity per capita, current solution quality, and addressable market size — and package each as a proposal in the spirit of Musk’s Hyperloop Alpha. This document is the proposal for loneliness & social isolation. Every number below is sourced and tagged with confidence. Every ranking is a conjecture, open to refutation.
Quantity · humans affected
1.5B
medSeverity · WTP / wealth
30%
medCurrent solutions
2.0 / 10
lowMarket size · TAM
$100.0B
lowWhat we are trying to solve
The 2023 US Surgeon General advisory found ~1 in 2 adults report measurable loneliness, with mortality risk comparable to smoking 15 cigarettes per day. Young adults and seniors are hit hardest. Causes are multi-factor: declining third places, smartphone displacement of in-person contact, atomized work, declining religious attendance. Tractable through deliberate community-building, in-person event platforms, therapy access, and cultural design. Severely missed by hard-tech problem lists because it resists technical framing.
The gap between the world and the world that is physically possible
Today: WHO calls loneliness a global health threat. ~1 in 4 adults report serious loneliness. Mortality risk comparable to smoking 15 cigarettes/day.
Current solution quality is rated 2.0 / 10 (low confidence) — meaning there is substantial unclaimed ground between what exists and what is possible. estimated — therapy + apps show modest effects; deep social-connection interventions hard to manufacture at scale.
Who is already working on this
4 entities are currently working on this problem across public markets, private companies, and research orgs. Each is evidence the market is real; none has obviously solved it.
Partiful
private · USAEvent-planning app that has become the default for in-person Gen-Z gatherings. Small but direct attack on atomization.
$150M
Timeleft
private · FRAWeekly dinners with five strangers in your city, matched by algorithm. Operating in 200+ cities worldwide.
undisclosed
Wysa
private · INDAI mental-health companion with over 6 million users globally. NHS and employer contracts for scaled access.
undisclosed
Marco Polo
private · USAAsynchronous video messaging to maintain real relationships over distance. Anti-algorithm social.
undisclosed
If we solve this, here is the world we get
After · 20 years
Default social architecture restored — third places, family proximity, community bonds rebuilt. Loneliness reduced to incidental rather than structural.
Requests for startups · 2 concrete companies to build
Third places as a business model
We optimized retail and offices and quietly deleted the places people simply *are* together. Build the company that makes the modern third place financially self-sustaining.
- why now
- Remote/hybrid work permanently changed where people spend their days; the demand for in-person belonging is unmet and growing.
- shape
- An operator of third places (not an app) with a unit economic model that does not depend on selling attention — membership, food, programming, or local commerce — and is replicable.
- success
- A profitable, repeatable third-place format exists and is expanding, measured by relationships formed, not engagement.
Proximity over feeds
Social software optimized engagement and corroded connection. Build the product whose only success metric is offline relationships formed.
- why now
- A generation raised on feeds is actively seeking alternatives; the cultural permission to build anti-engagement social products now exists.
- shape
- A social product engineered, instrumented, and financed around offline meetups and durable local ties — the opposite of a feed — with a business model that rewards that.
- success
- Users form measurably more real-world relationships, and the company is viable without an attention-extraction model.
full rubric + framing on the Requests for Startups page.
What the market can pay
The world is already paying $100.0B per year against this problem (US Surgeon General estimates $400B+/yr in US healthcare + productivity costs alone; global addressable wellness + community-tech market larger; low confidence).
A successful solution does not need to capture more — it needs to redirect a meaningful slice of existing spend, plus the latent willingness-to-pay implied by the severity score above. The cost ceiling for a real solution is bounded by this number; everything cheaper is dominated, everything more expensive is a non-starter.
What could go wrong, and how we know we are not wrong
Section in progress
Failure modes, ethical considerations, and the conditions under which this whitepaper would be falsified are being authored as the weekly cadence ships. The Deutschian commitment: every claim above is a conjecture; we publish the conditions under which we would update. New whitepaper sections ship with each Monday newsletter drop. Subscribe to get the upgrade, or contribute on GitHub.
Who would back this
Capital allocators with a stated thesis or deployed portfolio in this domain. This is a starting list — Exa Websets enrichment will expand it to direct check-writers per company.
O'Shaughnessy Fellowships
$100k for creators across domains, art, science, history, startups.
Where this is wrong, tell us
Every number on this page carries a source and a confidence tag. Every section open to refutation. If a citation is wrong, a number is stale, or a conjecture is unfounded — file a correction.
corrections → use the feedback widget in the nav · open issue at github.com/adamtpang/optimism.fun