Not distinguishable; not capable of being perceived, known, or discriminated as separate and distinct; hence, not capable of being perceived or known; as, in the distance the flagship was indisguishable; the two copies were indisguishable in form or color; the difference between them was indisguishable.
If a child from an Amazonian hunter-gatherer tribe comes to Boston, is raised in Boston, that child will be indistinguishable in language capacities from my children growing up here, and vice versa. Noam Chomsky
If you set out in a spaceship to find the one planet in the galaxy that has life, the odds against your finding it would be so great that the task would be indistinguishable, in practice, from impossible. Richard Dawkins