Raiders of the lost purpose (2): The stalactite principle

One of the most recurrent (and most disputed) headers during the last half century in the debates about whether cosmology points to some ‘fundamental purpose’ of the universe is (I didn’t need to say it) the (ill-)famous anthropic principle. Many versions of it have been formulated since it was so named in the 70’s, but discussions have concentrated on two ‘interpretations’ (the so called ‘weak’ and ‘strong’ anthropic principles), which in fact are so mutually different that it is not reasonable to take it as two different ‘versions’ of some more abstract or general idea, but as two ‘principles’ completely unlike each other.

stalactite principle
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The so-called weak anthropic principle (WAP) asserts that any explanation of the properties of the cosmos has to be consistent with the existence of beings that are sophisticate enough to look for such an explanation (i.e., it has to be consistent with our existence, that of human beings, or anthropoi, in Greek). This simply means that, if from a particular cosmological theory or conjecture it followed that beings like us could not exist, then that would be a sufficient reason to discard such a theory or conjecture. This ‘methodological rule’ is so trivial that one might find surprising that it has been elevated to the status of a ‘principle’: the real ‘philosophical’ or methodological principle that is functioning in this case is just the principle that theoretical conjectures have to be consistent with empirical data, i.e., a methodological rule like Karl Poppers’ falsificationism: it simply happens that the “empirical datum” that should be considered in this case is just the existence of human beings.

I think the only reason that might justify the hassle of formulating this trivial idea as a ‘principle’ is the fact that very often scientific arguments in cosmology circulate at a level which is too far from the kind of ‘data’ the WAP points to; I mean, cosmological discussions tend to be about very technical physical laws and scientific observations that refer in both cases either to the largest cosmic landscapes or to the smallest quantum phenomena, and scientists have to be kindly remembered that so to say ‘middle ground’ facts can be relevant in some cases.

But the truth is that, in the arguments involving the WAP, the existence in particular of the type of animals we know as ‘human beings’ is (very, very often) not that relevant: in all those cases, the argument will function exactly in the same way if we replace the concept of ‘human beings’ with the more general notion of ‘complex forms of life’. Actually, what most often these arguments tend to identify as the crucial datum to be taken into account is that the cosmological laws and constants permit the existence of a complex chemistry, which also most often reduces to the existence of an element as flexible in the creation of complex compounds as carbon, and of a molecule so versatile as dihydrogene monoxide (aka H2O, or ‘water’). Seen this way, the role of anthropoi (and even of ‘life’) in the ‘weak anthropic principle’ is ultimately irrelevant, and, in order to avoid any philosophical or metaphysical confusion, I propose to replace it with something that equally depends on the same chemical facts, but leaves less space for any temptations of mysticism. Hence I suggest replacing the ‘weak anthropic principle’ with what I would call the stalactite principle: the principle asserting that the laws of the cosmos, and the numerical values of the physical constants included in those laws, have to be consistent with the existence of stalactites. These amazing geological formations also depend, after all, on the wonderful chemistry of water and carbon (and other chemical elements, like calcium), and, not less importantly, on the existence of stable stars, and of planets with a not-too-stable rocky and humid crust orbiting around the former.

The laws of the cosmos, and the numerical values of the physical constants included in those laws, have to be consistent with the existence of stalactites

Before passing to consider, in the next entry, the strong anthropic principle (SAP), I have to comment a couple of issues that, notwithstanding my previous comments, make of the weak anthropic principle (and of our equivalent, but much more seasonable, stalactite principle) something not utterly trivial in the discussions about cosmology, after all. In the first place, this principle can work as a convenient counterweight to the much more important cosmological principle, often known also as the Copernican principle: the idea that our (spatial, temporal, or scale-relative) position in the universe is not privileged at all, or that the universe, considered in the sufficiently large encompassing ways, has to look exactly the same way no matter which perspective it is observed from. This rule, which is a kind of very general symmetry principle, has been the ground of many of the most important advances in our scientific understanding of the world in the last four hundred years, and for many consists in something more similar to a fundamental metaphysical principle of science than to a mere methodological prudential rule. Its truth, however, is no more than a mere conjecture beyond those realms in which it has been empirically helpful to describe our universe, and attempts to demonstrate its validity from some more general and self-evident principles have failed until now (cf. Beisbart 2009). The weak anthropic/stalactite principle asserts, however, that the cosmos couldn’t have been ‘observed’ from times too close to the Big Bang, for example, since no time enough would have passed to allow the emergence of things as complex as ‘observers’. This is not to deny the virtues of the Copernican principle, nor to get rid of it as a relevant criterion to assess the plausibility of different cosmological models, but just a reminder of its intrinsic conjectural nature.

The second aspect in which the WAP/stalactite principle plays, in its own triviality, a significant scientific role is as a reminder that the strong anthropic principle (the thesis that the existence of intelligent beings like us is not a mere cosmological datum to be explained together with many other ones, but something like a cosmological necessity) is also optional and conjectural, not something demanded by any kind of theoretical or metaphysical self-evident principles. In particular, since the constraints the stalactite principle puts to what cosmological theories have to be consistent with are empirically undistinguishable from what can be reasonably derived from the WAP, sensible methodological advice in these discussions would consist in replacing all the occurrences of the SAP with a hypothetical ‘strong stalactite principle’ (like ‘the laws of nature necessarily reflect the purpose of creating a universe that contains stalactites’), and, if the result sounds weird (as I guess it always will), then replace those occurrences with the more vacuous formulation of the (weak) stalactite principle. Stated otherwise: don’t presuppose that passing from the WAP to the SAP will improve at all the philosophical or scientific quality of your argument.


Beisbart, C. (2009) Can we justifiably assume the cosmological principle in order to break model underdetermination in cosmology Journal for General Philosophy of Science doi: 10.1007/s10838-009-9098-9

Mosterín J. (2005) Anthropic explanations in Cosmology, in Hajek, Valdés & Westerstahl (eds.), Proceedings of the 12th international congress of logic, Methodology and philosophy of science, North-Holland.

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