A number for the Montessori method.
For the first time, the method’s source material — which is huge, and public domain — can be read in full and held to evidence. And a number can be put on the method itself: a probability development model, assessed on a field basis, non-path-dependent.
The claim is made in four steps below. Every quote carries the page it was read from, and every count is recounted from the extraction artefacts when this page renders.
The method never fixed its order — by design.
Every witness deposed so far declines to fix the order of the materials and hands the decision away, in its own words — the Handbook to the teacher, Fisher to the mother, Stevens to the child. This is not an omission the books forgot to correct. It is a declared freedom, stated where the order itself is stated.
Handbook, 1914 — hands the order to the teacher
“The teacher may select according to her own judgment certain forms from among the whole series at her disposal.”
Fisher, 1913 — hands the order to the mother
“The order of exercises as hereafter indicated is to be followed with any ordinary child, but this must be modified according to circumstances.”
Stevens, 1913 — hands the order to the child
“For the order in which these have been taken up in this chapter is not one that is necessary to follow in practice with the children.”
Advanced, 1917 — hands the order to the child
“The children are free to choose the exercises they prefer; but of course, as the teacher initiates them in each exercise, they only choose the objects they know how to use.”
So every sequence is one lineage’s opinion.
Across 5,098 pair readings of the deposed witnesses, the books corroborate the catalogue and share not one ordering — all 17 surviving orderings are asserted by exactly one witness each — so a sequence-based assessment measures a lineage’s opinion, not the method (see the evidence).
What remains is a field, not a path.
the 1914 statement of the field’s founding coordinate
“The order which I have given refers to the degree of ease with which the child performs the exercises.”
Montessori’s own sentence says what kind of thing her order is: a gradient of ease — a coordinate to measure children against, not a curriculum to march them through. And 99.0% of the pair readings across the books assert no ordering at all. That is the size of the open space the method deliberately left, and it is where a field model lives.
So development is modelled as a field over the catalogue: each child holds a position and a gradient, updated by local observations of work on the materials — each material carrying its own criterion — with no dependence on the path taken to get there.
The number.
The instrument this yields is the probability development model: where the child sits on the field, what is ready next, and with what confidence.
What exists today is the framework, the corpus, and the test protocol. The composed field does not exist yet — the refinement loop that composes it from the evidence is in progress — so no calibrated number is claimed anywhere on this site. When one is shown, it will carry its evidence the way every quote here carries its page.
The test.
Photograph the work. Read the position. See the development path. The work record demonstrates that flow end to end today: recognition is staged and badged as a demonstration, and what it lands on is real — a position on the progression as the witnesses currently order it, every hop quoted and sourced.
The catalogue →
All 234 canonical materials, browsable — the object the field is defined over.
The work record demo →
Pick a mat, read it against the material’s own control of error, and see where the work sits.
The evidence →
The full apparatus behind this page: witnesses, spines, the computed method, and the provenance of every figure.