Five societies, from the 99.9th percentile to the edge of measurement

Thirteen original tests: THETIS (online, adaptive), RUFIT (online, timed), PROTEUS and QUADRAVA-FR (both online, untimed, with an instant certificate; certificates issued earlier for paper answer sheets remain valid), NEREUS and THAUMAS (online, untimed, four forms each), GALENE (online, untimed, new problems at every attempt), EIDOTHEA (online, untimed), and, from 5 November 2026, the adaptive online tests AMPHITRITE, DYNAMENE, PRONOE, PSAMATHE and PANOPEA, each up to the top of its scale (PANOPEA IQ 160+, PRONOE and PSAMATHE 180+, AMPHITRITE 225+ and DYNAMENE 250+), with your best result counting, as for THETIS. On every adaptive test a high score must rest on consistent success at the levels below it (its ladder), and it counts as the ladder holds it. Scores from other tests are not accepted: every member qualifies on the same, verifiable instruments.

Every result carries an integrity record: the test page notes what outside help leaves behind (leaving the test window, screenshot shortcuts, copy, paste or print attempts, AI assistant add-ons in the page), the server keeps its own times and checks the answer pattern, and the record is sealed with a fingerprint printed on the certificate. The author reviews it with every application, and a result that shows signs of outside help may be refused or withdrawn. A result does not need a supervised session before it counts for admission.

THETIS, yes: it is adaptive and draws new puzzles every time, so you may take it as often as you like, and your best certificate counts. NEREUS and THAUMAS, up to four times each: every attempt is on a form you have never seen, at least 90 days after the one before, and your best certificate counts. GALENE, up to ten times: every attempt is on problems you have never been shown, at least 90 days after the one before. AMPHITRITE, DYNAMENE, PRONOE, PSAMATHE and PANOPEA, yes: whenever you like once an attempt is finished, each on problems you have never been shown, and your best certificate counts. RUFIT, PROTEUS, QUADRAVA-FR and EIDOTHEA allow one attempt each.

Two classes for scores just below a society's criterion. The Nereid Society admits associate members from the 99th percentile (IQ 135 to 146, SD 15: one adult in a hundred), and the Aphotic Society admits subscribers from IQ 180 (to 189: about one adult in 21 million). Each class is numbered on its own, listed on the roll under its own heading if you wish, and receives its own certificate. A one-time admission fee of US$50 (associate members) or US$50 (subscribers) is paid with PayPal when you apply, and refunded in full if the application is not accepted. A later score that meets the society's own criterion admits you as a member.

Members of the Nereid, Aphotic, Hadal and Exocosm Societies pay no admission fee and no dues: the fee of the test you qualify with covers the review of your application (US$50 for RUFIT, the session fee for THETIS, the US$50 fee of the online test for PROTEUS, QUADRAVA-FR or EIDOTHEA, the fee of the attempt for NEREUS, THAUMAS, GALENE and the adaptive tests). Membership of the Mesopelagic Society carries a one-time fee of US$50. Associate members of the Nereid Society pay a one-time admission fee of US$50, and subscribers of the Aphotic Society US$50. There are no annual dues for anyone.

It is paid once, for life: US$50 with PayPal (a PayPal account or a card) when you apply, with no annual dues. Your application is checked before you pay, so nobody pays for one that would be refused, and the fee is refunded in full if the application is not accepted. Every member receives a numbered certificate of membership with the society's medal. A score of IQ 160 also meets the criterion of the Nereid Society, which you may join as well, with no fee.

A THETIS, RUFIT, NEREUS, THAUMAS, GALENE, EIDOTHEA, AMPHITRITE, DYNAMENE, PRONOE, PSAMATHE or PANOPEA certificate is checked automatically against the record on file, by its ID, your name and the score; a result of an adaptive test scored before its ladder (5 November 2026) is rescored by the author before admission, which may hold it lower. PROTEUS and QUADRAVA-FR certificates (online, or issued earlier for a paper answer sheet) are checked the same way, and an earlier score report without a certificate is checked against the author's records. Results flagged during a timed test (for example, leaving the test window) are reviewed before admission. The author confirms every membership by email, usually within 14 days.

Yes. Every member receives a membership certificate (PDF) bearing the society's own medal, the member's name and number, the admission criterion and the date of admission. Its ID and QR code lead to the Verify page, where anyone can confirm that it is genuine.

Only if you choose. The roll lists members who ask to be listed, with their country, qualifying test and date of admission; your email and score details are never shown.

They are positions on a test's own scale. On the normal curve, IQ 205 is rarer than one in 780 billion and IQ 220 rarer than one in 1.6 quadrillion, more than all the people who have ever lived. No test can verify such rarity against a population, so these two societies recognize the highest positions the THETIS, PROTEUS, NEREUS, THAUMAS and GALENE scales can record, with their margins of error. We say so openly, because that honesty is what gives the societies their value.