Abstract EANA2025-132

The Drake equation estimates the number of currently existing communicative civilizations in the Galaxy and, perhaps more importantly, enumerates the factors relevant for such estimation and highlights the degree of our uncertainty. Since its formulation in 1961, it has sparked extensive debate – ranging from praise as an indispensable tool for thinking about extraterrestrial intelligence, to criticism of its steady-state assumption and anthropocentric nature, and even dismissal as mere speculative popularisation. Nevertheless, it remains a basic and easily communicable framework for both interdisciplinary scientific discussion and public engagement.

From the perspective of the life sciences, a key shortcoming of the equation lies in its physics-centric formulation. While several parameters on the “left-hand side” of the equation – such as the rate of star formation or the fraction of stars with planetary systems – have been progressively refined thanks to advances in astrophysics, many of the “right-hand side” factors – those dealing with biology and social dynamics, such as the emergence of intelligence or technological civilizations – remain empirically underdetermined and conceptually unsettled. From our theoretical-biological viewpoint, the crucial point lies in the extent to which evolution, as a historical process, is (quasi)random, and to what extent it may follow law-like trajectories – being canalised, giving rise to directional trends, and, in the context of astrobiology, potentially leading to similar outcomes in different places. In this sense, the Drake equation serves as a lens through which this decades-old intellectual point of contention (e.g., Gould vs. Conway Morris debate) can be brought into focus.

Among the core objectives of our 4EU+ project “Uncertain Worlds: Rethinking the Drake equation and Earth’s Uniqueness” is to investigate how disciplinary background influences the estimation and interpretation of the equation’s parameters. Specifically, we examine how responses vary depending on the number and type of factors included, as well as the respondent’s field of expertise. Using an online questionnaire distributed among the general public, as well as academic and research communities, we compare three versions of the equation: the original formulation, a simplified version, and an extended version with additional parameters. In addition to collecting probability estimates, the questionnaire gathers qualitative information about participants’ backgrounds, beliefs, and familiarity with astrobiological topics. This allows us to analyse how different disciplinary profiles correlate with the quantification of parameters and to identify the most contested ones – particularly those whose interpretations vary across disciplinary boundaries (e.g., physics, life sciences, humanities). In doing so, the study offers empirical grounding for long-standing conceptual disagreements, potentially informing future reformulations of the equation and the assumptions guiding the search for extraterrestrial intelligence.

We will present the project and initial results based on early responses from its initial phase (summer 2025). Beyond its scientific relevance, the project seeks to foster interdisciplinary dialogue, encourage critical reflection on humanity’s place in the cosmos, and contribute to science education by highlighting the complex and contingent conditions that make life – and intelligent, technological life in particular – possible.