The weak anthropic principle states that in a universe that is large or infinite in space and/or time, the conditions necessary for the development of intelligent life will be met only in certain regions that are limited in space and time. The intelligent beings in this area should therefore not be surprised if they observe that their locality in the universe satisfies conditions that are necessary for their existence.
…According to [the strong anthropic principle], there are either many different universes or many different regions of a single universe, each with its own initial configuration and, perhaps, with its own set of laws of science. In most of these universes the conditions would not be right for the development of complicated organisms; only in the few universes that are like ours would intelligent beings develop and ask the question: “Why is the universe the way we see it?” The answer is simple: if it had been different, we would not be here!
The Anthropic Principles: Ideational, Interpersonal, and Epistemological Dimensions
(1) The Weak and Strong Anthropic Principles
As Dawkins (2006: 135) notes, the term anthropic principle was coined by Brandon Carter in 1974 and further developed by John Barrow and Frank Tipler (1988).[1] Carter’s basic claim is that the very fact of human existence provides information about the nature of the universe: it places constraints on what the universe must be like — an argument that proceeds from effect to cause.
Hawking (1988: 124–5) distinguishes the weak and strong versions of the principle:
The weak anthropic principle states that in a universe large or infinite in space and/or time, the conditions necessary for the development of intelligent life will only occur in certain regions, limited in space and time. Intelligent beings in such regions should not be surprised to observe that their local conditions happen to support their existence.
The strong anthropic principle proposes that there are either many different universes or many different regions of a single universe, each with its own initial configuration and possibly its own laws of science. In most of these, conditions would not support complex organisms; only in the few universes like ours would intelligent beings evolve and ask: “Why is the universe the way we see it?” The answer: if it were different, we wouldn’t be here.
Both versions attempt to account for the apparent “coincidence” that the fundamental constants of physics are exactly those needed for the emergence of intelligent life — that is, to explain why, out of all possible universes, the one known to physicists is precisely suited for beings capable of understanding it.[2] However, as explored below, anthropic reasoning often involves a series of ideational inconsistencies, interpersonal motivations, and epistemological confusions.
(2) Ideational Inconsistencies
Some forms of anthropic reasoning confuse result with reason: science models intelligent life as an effect of the universe’s initial conditions and dynamics. Anthropic reasoning, however, reverses this logic — treating intelligent life as the reason for those conditions.
More strongly still, some versions confuse result with purpose: intelligent life, as an outcome of specific physical conditions, is reinterpreted as the goal or objective of those conditions. This attribution of purpose to the universe models it as if it were an organism — mapping models of purposeful human behaviour onto models of cosmic evolution.
(3) Interpersonal Motivations
By reframing intelligent life as the reason or purpose of the fundamental constants — rather than as one among countless possible outcomes — anthropic reasoning reinterprets the contingent existence of humans (modalisation: probability) as a necessary inevitability (modulation: obligation).
This shift serves an interpersonal function: it elevates the status of humans, implying that we are not only significant but central — the point of the universe.
Given that nearly everything else in the universe would not have emerged under different constants, anthropic reasoning smuggles in the judgement (by humans) that the human activity of modelling the universe is more valuable than all the other processes in the universe.
(4) Epistemological Confusion
This special valuation of modelling is sustained by an epistemological confusion discussed earlier: namely, the assumption — prevalent in some physics discourse — that the mathematical equation is not just a model of categorisation, but a mirror of reality. On this view, the physical universe forms one side of an equation, while the theoretical model forms the other. The task of science becomes the search for a perfectly symmetrical match — a “true” model of a “real” world, whose categories exist independently of categorising systems.
This is the context in which some physicists, following Einstein, express wonder at the “good fortune” that humans are able to understand the universe (equated with the laws of physics). If this is not mere coincidence, then — the reasoning goes — humans must be of special significance.
A less self-aggrandising — and more ideationally consistent — interpretation is simply this: humans can only construct models that humans are capable of understanding.
(5) The Participatory Anthropic Principle
Other versions of the anthropic principle have also been proposed. One example is the Participatory Anthropic Principle (Wheeler 1983), which claims that all existents — past, present, and future — are brought into being through acts of observation by all observers who have ever existed.
This view again rests on a failure to distinguish between categorisable phenomena and the categories constructed by observers. Once this distinction is recognised, the Participatory Anthropic Principle can be reframed: phenomena are not categorised until observed. What humans create are not universes, but models of the universe — models that function for humans, not the universe itself.
Notes
[1] Carter has since suggested that the term cognizability principle more accurately captures what he intended (Dawkins 2006: 392), namely the astonishment of physicists that the universe is intelligible at all.
[2] It could be argued that anthropic reasoning is the physical analogue of William Paley’s Argument from Design, invoking a (mathematical) designer that transcends the universe — a case of mathematical physicists seeing God in their own image.
[3] For example, the Final Anthropic Principle (Tipler 1989) claims that intelligent life must arise in the universe, and, once arisen, must persist until the end of time.