About THETIS
Reasoning when the rules are hidden, and when they change
THETIS measures one thing: how well you infer a hidden rule from evidence, test it, and update it when the evidence shows the rule has changed. We call this abductive–dynamic reasoning. It is the heart of fluid intelligence, and it can be measured without words, school mathematics or anything you could have learned.
The construct
Abduction is inference to the best explanation: from a handful of observations, find the simplest rule that accounts for all of them. Dynamic means the rule may change partway, and the solver must notice the moment the old rule stops fitting and adopt the new one.
Every THETIS puzzle follows one principle, inherited from PROTEUS: the answer is what the simplest explanation of everything shown predicts. A rule that has changed keeps its new form until the evidence shows another change. Every puzzle is checked by computer: under its rules, exactly one option follows from the simplest explanation, and every wrong option comes from a typical reasoning error.
Four skills, seven families
- Abductive inference: finding the rule behind new material.
- Dynamic updating: noticing a change of rule and adopting the new one.
- Hypothesis testing: checking a candidate rule against every piece of evidence.
- Uncertainty management: holding several explanations until the evidence decides.
The puzzles come from seven families: Mutable Matrices, Drifting Strings, The Oracle's Ledger, Translations, Levers and Lamps, Turnstiles and Orbits. Each family stresses the skills differently, and the score report shows seven facet scores built from them.
Why no words and no arithmetic? Vocabulary and school mathematics measure what a person has learned, which depends on schooling, language and opportunity. Fluid reasoning is best seen in material that is new to everyone. THETIS uses only shapes, cells, cards, lamps, marbles and rings, and its instructions can be read in English, Spanish or Mandarin.
Why adaptive? A fixed test measures precisely only near its own difficulty. THETIS chooses every puzzle to measure best at your current estimate, so it is as precise for a person at IQ 90 as for one at IQ 190, in about 30 puzzles.
How a THETIS session works
Three introduction screens
What THETIS measures, how the adaptive engine works, and how to move through the test, in English, Spanish or Mandarin.
A practice module of 14 puzzles
Two from each family, with the reasoning explained after every answer. The scored test opens once you have worked through all fourteen.
About 30 adaptive puzzles, untimed
The first five are of average difficulty; harder puzzles open only after you show mastery at the level below. One careless early mistake cannot sink a score: the model allows for slips.
Your report, at once
Deviation IQ with its 95% range, percentile, seven facet scores, a confidence-calibration index, estimated equivalents on other scales, and a certificate anyone can verify.
The project and its author
Resquites High-Range Tests is the work of Jo Christopher Resquites, MEng: licensed agricultural and biosystems engineer, ambassador of the Triple Nine Society for the Philippines, member of Mensa and Intertel, and a former Fellow of the International Society for Philosophical Enquiry. He wrote every problem on this site: THETIS, RUFIT (first published in Telicom in 2021), PROTEUS and QUADRAVA-FR.
The tests are independent. They are not published, endorsed or administered by Mensa, Intertel, the Triple Nine Society, the International Society for Philosophical Enquiry or any other organization.
Standards we hold ourselves to
- Every score with its margin of error, and norms labeled provisional until human data confirm them.
- Methods published: the item model, the adaptive algorithm, the stopping rule and the simulation results are in the technical manual.
- No inflated claims: above about IQ 190 a score is a position on a test's scale, not a counted rarity, and every report says so.
- Privacy: no email or score is ever shown publicly; certificate holders may hide their name.