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How does the small value of the cosmological constant relate to anthropic reasoning?

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Anthropic principle The Hubble Deep Field. This image, the result of 10 days' observation by the Hubble Space Telescope, shows 1,500 galaxies in different stages of their evolution.

The small value of the cosmological constant is a central topic in anthropic reasoning within cosmology. While the cosmological constant—often associated with dark energy—is observed to be very small, theoretical models often suggest it should be much larger.12

In the context of the multiverse, specifically models like the eternal inflation/string landscape, physical constants can take on a wide range of values across different regions of space-time. Anthropic reasoning posits that because life requires specific conditions to arise and persist, we should not be surprised to find ourselves in a region of the multiverse where the cosmological constant is compatible with the existence of observers.23

If the constant were significantly different, it might prevent the formation of galaxies and stars, thereby precluding the development of complex life. Consequently, the observed small value is interpreted by some as a selection effect: life necessarily exists only in those rare regions where the constant allows for a life-supporting universe.32