# The cosmological theory of inflation

## Problems, possible answers, and computational complexities

Kristina Šekrst

*Croatian Studies, University of Zagreb*

*Faculty of Humanities and Social Sciences, University of Zagreb*

AbstractThe cosmological principle states that at each epoch, the universe is the same at all locations and all directions, besides the local irregularities, i. e. globally the universe is assumed to be homogeneous and isotropic at given time: on a large scale usually greater than 100 Mpc, but it is not on scales up to that limit. In modern cosmology there are three puzzles. The first one is why is the universe so uniform on large scales (the horizon problem), the second one is why is the geometry of the universe almost flat (the flatness problem), and the third one is where do fluctuations in large-scale structure come from, as a source of future stars, galaxies and clusters, along with the monopole problem regarding magnetic monopoles predicted to exist in Big Bang cosmology.The inflation theory, as the exponential expansion of space, with a less accelerated rate after the period of inflation, tries to give some answers to these puzzles since the early 1980s. It implies a much bigger universe than the observable one: the inflation never ends in the universe, and the central role is given to the concept of false vacuum — a metastable state characterized by higher energy than the rest, negative pressure and strong repulsive gravitational field — which, as a probabilistic process, drives the accelerated cosmic expansion, for the universe undergoes a phase transition from false vacuum to a ground state with a great amount of energy released.

The goal of this talk it to shed some light on the philosophical consequences of this theory: to compare the inflational models with some ancient and modern philosophical ones as possible equivalents or alternatives; to see the possible problems — such as fine tuning and creation problems — which seem to arise; and to observe the notion of causality, all along with the possible computational complexity observations regarding key moments and concepts.