The Penultimate Set Fallacy

We know that we do not know, what we do not know.

A common street hustle in Europe and Africa begins with the claim “There is only one thing we do not have, and all you have to do to make this happen is _____________.”  That blank, is filled with a menagerie of cost, counter-evidence and complexity, which the claimant implicitly denies in its offing.  The Penultimate Set fallacy is the furtive presumption expressed or implied by a claimant, that enough knowledge is held by the claimant to reduce or eliminate the salient impact of unknowns within a discussed domain.  In this inductive logical fallacy of presumption, more broad but conditionally related to the No True Scotsmanfallacy, it is implied that unknowns inside a domain are all identified, further then these ‘gaps’ in knowledge constitute a sufficiently insignificant impact on the domain, and/or finally that this minority of unknowns in no way compromises a claim to authority.  This fallacy is a danger when employing the ‘God of the Gaps’ counter argument inside natural theory, which while valid as an argument in a generic sense, becomes invalid when contended based on a Penultimate Set fallacy.

How the Penultimate Set Scam Works at Face Value

We just lack one thing from you which is preventing utopia from effervescing forth.

This 3-step artifice is a very common hustle employed in the third world as well as the largest institutions in the Western world. After observing this ruse many times in Asia and Africa, I have given it the moniker The Penultimate Set Scam (or Fallacy when contended in the objective).

The hustle always falls along these lines:

1. Everything is, was or can be perfect (the substrate),

2. something you are not doing is causing this perfection to be stultified (the sin),

3. we just lack one thing from you which is needed in order to fix this (the mark),

(there is a fourth requisite part – this thing you need to provide needs to happen now)…

Whereupon bountiful utopia will be precipitated into reality and all perfection will be realized. The substrate is always different, the shortfall is always in your camp, and the mark usually involves money, fealty or politcal power.

If there is one projected character trait of a supreme intelligence (whatever that is) in the cosmos, which I surmise, it is that such an intelligence will NOT practice this scam methodology, as a measure and feature of its interaction with the lesser beings which inhabit the cosmos.

But yes, fake SSkeptics sell this very same scam.

You see it’s simple really. All knowledge is already there, and all we lack is critical thinking on your part.

Penultimacy in this context means that the claimant presumes to hold ‘the next to last piece of information knowable.’  Therefore the gaps in the claimant’s knowledge are insignificant or substantively irrelevant.  It is fallacious in the logical sense that ‘we do not know, what we do not know’ so an implied penultimate knowledge is likely, or can be shown to be, a false underpinning of an argument.

Penultimate Set


A penultimate set is a sub-domain of assumptions or proofs which are contested as chiefly, substantially or sufficiently representative in describing the salient features of the broader domain.  It is the boast that my knowledge or the knowledge of science, or the expertise of a particular discipline sufficiently describe a construct or natural realm such that only minor gaps remain our understanding of that discipline.

A claim of penultimacy is not automatically fallacious, hence its inductive categorization; however, this status does not excuse the employment of the presumption, especially when implied rather than stated. Even a legitimate authority speaking on his area of expertise may hold a minority of knowledge in that field, and not yet be aware of this.  So absolutism in any given field is not guaranteed to be valid.

This informal fallacy occurs most commonly when a claimant either (a) is not an authority, or (b) is not an authority on the subject on which he is being cited.  However it can easily occur by commission, when the claimant is indeed an authority as well.  If someone either isn’t an authority at all, or isn’t an authority on the subject about which they’re speaking, then that undermines the value of their testimony, based on the likelihood of the Penultimate Set fallacy.


(1) We have gathered and analyzed the facts surrounding the whereabouts of Jimmy Hoffa.
(2) His murderer needs to be identified by you

This argument is fallacious because the presumption is made that the only step remaining, is to identify the murderer, when the set of other possible events are still extant; including things of which we have not thought or were not even aware existed.  It is an implied boast on the part of the claimant in line (2).  In this case the ‘gaps’ in the knowledge domain may be constrained, and we are able to identify that there are other, granted unlikely, scenarios which could have occurred.  Jimmy could be hiding out somewhere, or he could have been riding his bike and fallen into a volcano, or he could have become ensnared in fishing line in a lake near his home and drowned.  However, in domains less precise than this example, the concerns over the Penultimate Set fallacy grow larger.  The ‘gaps’ may constitute the majority of the domain in question, and indeed we may not even be aware of these things we do not know or features we have not observed nor understand.  The appeal to this logical fallacy therefore, enables the counter argument to be ethically posited, in a non-pejorative context toward the knowledge domain claimant.

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