Self-propagating (embodied and distributed cultural) systems of emergent complexity featuring intelligence as a tool of reflexive context-exploitation (on a spectrum of sophistication culminating in whatever it is that this very young technological civilisation we are embedded within is) has emerged at least once.
Of course, we may not actually recognise extraterrestrial life when we observe it elsewhere. It is possible that our own peculiar and unique material incorporation and the character of our (narrative, reflexive and symbolic or cultural) experience predisposes us to generate foundational assumptions and procedural investigative axioms biased towards a more probable (or at least – expected) and limited spectrum of possibility for life or intelligence. Astrobiology is a rich and deep possibility-space and I think we would do well to be prepared to reshuffle our assumptions through creatively useful recombination.
There is perhaps a certain logical necessity to the emergence of complex, self-propagating (embodied, experiential and distributed cultural, information-processing) systems. Self-gravitating systems indicate in relatively simple ways that intuitive component of a conceptual vocabulary that portrays a system in profound recursive (material, physical) self-reference. This is a concept which extends smoothly into considering that any system of sufficient sophistication and complexity possessing open-ended properties of accelerative compression (and its corollary of disseminative, dispersive decompression) is, when viewed as a whole, fundamentally a recursive system of self-accelerating, self-gravitating internal self-reference. Systems continuity and the emergence of useful, creative complexity harness the implicit and constitutive logical discontinuity of a holistic systems theory in mischievous ways.
Suspending the full consequences and intrinsic logical enigmas endemic to holistic systems-theoretical frameworks may be necessary to allow for communication or concept-development in this space. It is however simultaneously true that only by embracing the various paradoxes and discontinuities intrinsic to considerations of complete and total or whole systems can the broadly distributed, perhaps holographically organised, core principles and symmetries of such systems be identified and usefully exploited. In this the principle of intelligence as successful, goal-seeking or directed context-exploitation attains a certain meta-systemic utility (despite that on a holistic level of logical or systems analysis, all reference and system development is by internal extensivity; e.g. Cantor’s diagonalisation proof or Gödel’s diabolical tangled hierarchies of recombinatory axiomatic metamorphosis).
Identifying atomic entities or components of complex systems and of living and information-processing systems is itself a complex activity. The system primitives of such a study are themselves also the axioms that through recombinatory boot-strapping in complex symmetries and multidimensional vector spaces generate their own logical (and enigmatically discontinuous) necessity.