In this blog post, we scientifically explore whether the multiverse could actually exist or if it is merely a concept confined to the realm of imagination.
Everyone has likely encountered fantasy novels, sci-fi films, or comics that explore the existence of another version of oneself or parallel worlds. These stories stimulate our imagination, painting a captivating world where events deemed impossible in reality unfold. For instance, imagine a person with your exact appearance and personality living in another dimension, or discovering another version of yourself leading a completely different life in another world. What if these things weren’t confined to imagination but actually occurred within the universe we inhabit?
Indeed, many physicists believe a world could exist where universes identical to ours, or entirely different ones, coexist. They refer to this concept in physical terms as the ‘multiverse’ and propose various theories predicting its existence. This idea has resonated deeply not only in science but also in philosophy and literature. In particular, multiverse theory raises fundamental questions about the nature of human existence, the concept of free will, and the role of destiny, offering a new perspective that transcends existing scientific paradigms.
However, the multiverse theory has been a subject of debate since its initial proposal. It still lacks sufficient evidence to be considered a complete theory and has many points requiring refinement. While the theory presents fascinating possibilities, concrete evidence and experimental verification remain scarce. Consequently, the multiverse theory remains highly controversial among some scholars and stands at the center of debate within the scientific community. From here on, we will discuss the problems with these multiverse theories and explore whether a multiverse could truly exist.
Physicists cite the following reasons for why a multiverse must exist. First, from the perspective of quantum mechanics, which is based on probability, the introduction of the multiverse concept is essential to explain why only one specific outcome is derived from the many possible results that could appear. For example, consider the act of flipping a coin. Everyone knows that the probability of heads is 50%, and the probability of tails is also 50%. The problem begins here. When the coin is actually tossed, only one outcome—heads or tails—materializes. So where does the probability of the other outcome go? Quantum mechanics holds that the probability of this other outcome cannot be ignored. Therefore, the multiverse theory posits that the remaining probability branches off like a fork in the road across the multiverse, giving rise to an infinite number of other possible outcomes following that probability. From this perspective, the uncertainty principle of quantum mechanics provides a crucial foundation supporting the multiverse theory, suggesting that every event in the universe can lead to diverse outcomes within the multiverse.
Second, the probability that beings like us could exist in the universe has already been proven by our very existence. Therefore, assuming the entire space of the universe is infinite, the total number of possible cases is infinite. Thus, the product of infinity and the probability of our existence becomes infinite. Similarly, consider shuffling a deck of 52 cards numbered from 1 to 52. The probability of randomly shuffling these cards into the exact sequence from 1 to 52 is extremely low. However, if the cards were shuffled an infinite number of times, the sequence from 1 to 52 would appear an infinite number of times. This leads to the conclusion that countless beings like us exist throughout the cosmos, and thus that multiple universes exist. Theoretically, this implies that every possible universe could be real, offering profound insights into the nature of the universe and humanity’s place within it.
To contemplate this multiverse theory, we must reconsider the definition of infinity. Infinity refers to a state of perpetual expansion, a state without end. In multiverse theory, after assuming the universe is infinitely large, we multiply this by the probability of our existence to conclude that beings like us exist in countless numbers. But what if the probability of our existence is one in infinity? In the cosmos, if space is infinite, life forms like humanity might exist by chance through the probability of appropriate molecular arrangements. But for humanity in our specific state to emerge, an even more infinite probability would be required. To align with our constantly changing actions, an enormous probability must be multiplied every hour, no, every second. Therefore, the probability for humanity like us to exist is an infinite fraction multiplied by an ever-increasing probability, ultimately becoming an infinite fraction. This discussion raises serious doubts about the reliability of multiverse theory and demands a reexamination of the physical interpretation of the concept of infinity.
Therefore, multiplying infinity by one over infinity is problematic because there is no guarantee it results in infinity due to the extreme concept of indeterminacy. Furthermore, multiverse theory fundamentally assumes the entire universe is infinite in size. However, according to Hubble’s law, the observable universe is roughly the size of a circle with a radius of 2 million light-years. Other universes cannot be observed. Therefore, no matter how well-established the multiverse theory may be, it seems difficult to accept because there is no way to actually prove the theory through observation. The multiverse theory is an intriguing concept, but its difficulty in experimental verification places it at the center of debate within the scientific community, posing a significant obstacle to the theory’s development and application.
We have discussed the perspectives of multiverse theory and its problems thus far. It is undeniable that the multiverse theory, proposing the existence of countless other universes beyond our own, presents a new paradigm for interpreting the universe. However, for this paradigm to be truly recognized as a scientific theory, experimental evidence and logical consistency are essential. For multiverse theory to be formally established as a theory, solutions to these logical problems must be presented, and it appears that many other issues must also be addressed. The advancement of science has always been accompanied by new challenges, and multiverse theory will be one such challenge. Through the process of theoretical discussion and experimental verification, we can take another step toward a deeper understanding of the nature of the universe.
