apodictic machine-checked praxeology

1.9. The vocabulary๐Ÿ”—

Reference. These are the definitions the statements above are written in; nothing earlier depends on having read them.

The basic vocabulary is deliberately bare. Preference is just a relation: not assumed transitive, not assumed to rank every pair, and time is not assumed ordered. Properties get added when a theorem forces them, and so far none has.

๐Ÿ”—structure

The vocabulary everything else is built from: bare types and bare relations. Nothing here has any property. Preference is not assumed transitive, not assumed to rank every pair, and Time is not assumed ordered. A property gets added only when some theorem forces it, and every such forcing is a finding.

Agent : Type

Acting persons.

End : Type

Ends: states of affairs an agent may value.

Means : Type

Means: scarce resources an agent may employ.

Time : Type

When action happens. Explicit from the start; no order assumed yet.

Believes : self.Agent โ†’ self.Time โ†’ self.Means โ†’ self.End โ†’ Prop

Believes agent time means want: at that time, the agent believes that using those means helps bring about that want. Nothing links a means to an end here except what the agent believes.

Prefers : self.Agent โ†’ self.Time โ†’ Set self.End โ†’ Set self.End โ†’ Prop

Prefers agent time X Y: at that time, the agent values the bundle of ends X above the bundle Y. This is the ranking behind the agent's choices, read as strict โ€” but that reading is not assumed anywhere: NO properties are imposed on this relation, strict or otherwise, and a theorem that needs one says so. It is kept apart from what the agent actually does; nothing in the library bridges the two, and the claim that would (demonstrated preference) is parked, carried by no theorem.

It ranges over SETS of ends rather than single ends. The tradition draws no line between an end and a composite of ends โ€” "atomic" only ever means "not divided further by this action", the same relativity as the size of a unit of supply (MES p. 28). So there is ONE ranking, over bundles at whatever grain the problem has, and an end in the ordinary sense is a bundle with one member (PrefersEnd). Ranging over bundles is what lets independence of uses โ€” bundle preference breaking down into preference between ends โ€” be a named hypothesis, instead of something the vocabulary quietly enforces.

Shape claim (audit): a bundle is a Set, so it carries no multiplicity and no order.

๐Ÿ”—def
Apodictic.ActionFrame.PrefersEnd (praxis : ActionFrame) (agent : praxis.Agent) (time : praxis.Time) (want other : praxis.End) : Prop
Apodictic.ActionFrame.PrefersEnd (praxis : ActionFrame) (agent : praxis.Agent) (time : praxis.Time) (want other : praxis.End) : Prop

Preference between two single ends. This is bundle preference between two one-member bundles โ€” a definition, not a second relation.

The law is about a stock of units and what the agent would do with more or fewer of them.

๐Ÿ”—structure
Apodictic.Stock (praxis : ActionFrame) (agent : praxis.Agent) (time : praxis.Time) : Type
Apodictic.Stock (praxis : ActionFrame) (agent : praxis.Agent) (time : praxis.Time) : Type

A stock of some good, held by one agent at one time: finitely many units the agent believes will do the same jobs.

"The same jobs" is the whole of what homogeneity means here. Each unit is believed to serve exactly the ends in serves, and that is a claim about BELIEF, not about preference. Nowhere is it said that the agent is indifferent between units. So preference can stay strict, and Rothbard's denial that indifference is ever demonstrated in action is not contradicted. Whether doing the same jobs is enough for the law, or whether indifference between units is needed after all, is then something to check rather than something assumed away.

What counts as a unit is left open: units lists whatever enters the action as one thing. Rothbard holds that the law works "regardless of the size of the unit considered. The size of the unit will be the one that enters into concrete human action" (MES p. 28). Pairs of horses make a different stock, with a "new and shorter scale of ends", and a good that "cannot be divided into homogeneous units for purposes of action" is a stock of exactly one unit.

units : Finset praxis.Means

The units of the good on hand.

serves : Set praxis.End

The ends this good can serve, by the agent's lights.

unitsAlike : โˆ€ unit โˆˆ self.units, โˆ€ (want : praxis.End), praxis.Believes agent time unit want โ†” want โˆˆ self.serves

Every unit is believed to serve exactly the ends in serves.

๐Ÿ”—structure
Apodictic.AllocationPlan {praxis : ActionFrame} {agent : praxis.Agent} {time : praxis.Time} (stock : Stock praxis agent time) : Type
Apodictic.AllocationPlan {praxis : ActionFrame} {agent : praxis.Agent} {time : praxis.Time} (stock : Stock praxis agent time) : Type

The agent's plan for the stock: for each subStock โ€” each set of units he might have โ€” the ends he WOULD serve with exactly those units, at the stock's single time.

This is something new, over and above Action, and it has to be. A single act of allocating cannot tell the served ends apart from one another โ€” they all sit inside the one package chosen. So what the law of marginal utility rests on is not action at all: the plan is a separate thing, and no act of the agent's exhibits it.

The plan is indexed by WHICH units, not by how many. To say it depends only on the number of them is to say the units are interchangeable, and that is not built in here: it is the named condition Homogeneous, assumed only where a theorem needs it.

Field-shape claim (audit): servesOnlyWhatItCan is the one condition left in field position, and it is definitional โ€” a plan that puts a unit to an end the good is not believed able to serve is not a coherent plan, rather than a situation that might obtain.

One unit to one end is NOT here, and is nowhere: no theorem needs it. Rothbard assumes it and says he is assuming it โ€” "each unit of means is capable of serving one of the ends", introduced with "We assume for simplicity" (MES p. 26) โ€” and the ordering the law asserts turns out not to want it. Where an extra unit adds no new end, the law is silent, which costs nothing.

wouldServe : Finset praxis.Means โ†’ Finset praxis.End

The ends the agent would serve with exactly the units in subStock, and no others.

servesOnlyWhatItCan : โˆ€ (subStock : Finset praxis.Means), โˆ€ want โˆˆ self.wouldServe subStock, want โˆˆ stock.serves

A unit is only ever put to an end the good is believed able to serve.

Two conditions sit a level down, as fields of the two structures every theorem above takes as arguments. servesOnlyWhatItCan says a unit is only ever put to an end the good is believed able to serve. unitsAlike, a field of the stock, says every unit is believed to serve exactly the same ends โ€” and that is what fixes the range of stock.serves, which is in turn what the one claim quantifies over. Neither is a binder in any statement, and both are on the manifest regardless: #manifest reads one level in and reports them, because whoever supplies the argument has already discharged them.

The two are not alike, and the manifest does not pretend otherwise. A plan that puts a horse to a job the man does not believe a horse can do is not a situation that might obtain โ€” it is an incoherent plan, so servesOnlyWhatItCan assumes nothing about the world. A lame horse is a situation that might obtain, so unitsAlike does. Which of the two a carried condition is cannot be read off the term; it is ruled by hand, and this is the ruling.

A third used to sit here, and now sits nowhere. One unit to one end can fail of a real stable โ€” two horses to one wagon, or a horse standing idle โ€” so it could not stay a field. Taking it out showed that no theorem wants it, so it was not made a hypothesis either. See the findings.

Interchangeability of units is not hidden down there. The plan is indexed by which exact units the man holds; that it depends only on how many of them there are is a separate named condition, AllocationPlan.Homogeneous, given in full under The conditions along with the other two.