The Turing Test is basically the idea that when (a) computer and a human can't be differentiated, that computer is an AI.

Identity of Indiscernibles boils down to if A is indistinguishable from B then A = B

Suppose now that AI is realized/actualized. Since this AI can't be told apart from humans, it follows that AI = humans.

If so per The Indiscernibility of Identicals rule, a dilemma on our hands:

  1. AI is sentient because we're sentient.
  2. We're not sentient because AI is not sentient.

What are the implications of The Leibniz-Turing Dilemma?

  • Maybe that we can use it as a negative criteria for discernibility: if a specific behavior can be replicated by a computer, than it is not an "essential" trait of human intelligence. Feb 5, 2023 at 8:18
  • The Turing test is just a minimal standard that a "human-like" AI should pass. And even if the AI passes something much stronger the dilemma will much depend on how exactly it was "realized". If we grow humans in a Petri dish few will have a problem with ascribing "sentience" to them. If the "realizing" of the AI is similarly opaque (it already is opaque even for commercial ANN today), there will be no dilemma either. The dilemma will only emerge if the realization is such that it gives us strong reasons to disbelieve the AI's "sentience". I have no idea why that would be the case.
    – Conifold
    Feb 5, 2023 at 8:52
  • @MauroALLEGRANZA, is not thinking an essential feautre of being human?
    – Hudjefa
    Feb 5, 2023 at 9:07
  • @Conifold, the dilemma arises if we give our nod of approval to the identity of indiscernibles and subsequently the indiscernibility of identicals.
    – Hudjefa
    Feb 5, 2023 at 9:09
  • The Turing Test involves a test to see if you can tell a human from a computer only by interacting through an interface. The identity of indiscernibles doesn't allow for such limited testing. If there is any possible way of detecting a difference, then it doesn't claim identity. Feb 5, 2023 at 9:21

2 Answers 2


The comment you appended to the excellent answer by Paul Ross shows that you are missing an important point. You can make almost any pair of objects indistinguishable by imposing constraints on one's ability to distinguish them. If I expose only a square inch of my old Isuzu pick-up truck you might find it indistinguishable from a corresponding glimpse of a Rolls Royce- does that mean my truck is a Rolls Royce? Clearly not. The example might appear trivial, but it illustrates the principle- if AI seems indistinguishable from humans only in a limited sense, then you cannot assume that AI has all of the properties of humans. You therefore need to rephrase the question as follows: given that AI has a given subset of capabilities that are observably indistinguishable from those of humans, does that mean AI is sentient? To answer that question with any degree of confidence you would need to have an accepted theory of consciousness.

  • That's a good analogy. The question is what is the correct yardstick for AI-human comparison?
    – Hudjefa
    Feb 5, 2023 at 9:29
  • @AgentSmith Marco is right: the equality does not hold, because only one little property of both was considered. There is no generalization that holds from that. But, why even try to compare a piece of software to humans?
    – Frank
    Feb 5, 2023 at 16:21

The limitation here is that the identity of indiscernibles is a metaphysical principle, not a principle of any form of distinguishability. A machine constructed from fabricated silicon wafers is distinct from a human who has been born and grown organically, and while you can construct a linguistic communication framework in which the two can produce identical behaviours, that doesn't mean you can apply the Leibniz principle to it.

Now, if you're asking about the question of building an ontology e.g. for machine learning, then there is something interesting to ask about whether you might treat a person as essentially a very sophisticated form of AI agent. But that works only in a particular context of sense - when they report a malfunction with their internal process, you send a doctor rather than an electrical engineer (at least, if you wanted to help!)

  • What distinction we zero in on matters then. However, Alan Turing's genius shines through ... we're to ensure that the playing has been leveled so to speak - no physical features will be revealed, only mental processes are accessible to the tester/examiner.
    – Hudjefa
    Feb 5, 2023 at 9:06
  • Mental processes are notoriously not accessible to external examination - we read them indirectly through their supervenience on the physical. That's exactly why a system of physical symbol exchange is appealed to as an intermediary over which to conduct the test, and this invites the problem of engineering the context to favour a certain model of distinguishability.
    – Paul Ross
    Feb 5, 2023 at 9:13
  • True and hence the dilemma, oui?
    – Hudjefa
    Feb 5, 2023 at 9:34
  • But it doesn't seem to be a well structured "metaphysical dilemma" (in the force of the Leibniz principles) if the distinction at work can be pulled apart in multiple directions. You don't have to say "humans aren't sentient" in order to think that there might be a plurality of competing, disagreeing sentience concepts under evaluation, and that no one of them takes metaphysical priority over the others. And just as there might be a plurality of concepts, so too could feature a plurality of Turing tests emphasising the respective sentience notions.
    – Paul Ross
    Feb 5, 2023 at 10:03
  • I intelligo. I'm, let's just say, working within the metaphysical limitations/boundaries Alan Turing and Leibniz were.
    – Hudjefa
    Feb 5, 2023 at 12:37

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