From: mk_thisisit
The Unification Challenge
The universe is described by two major theories developed over 2,000 years of research: the theory of relativity and quantum theory [01:52:43]. The theory of relativity describes “great things” such as the Big Bang and quasars [02:01:14], while quantum theory describes “small things” [02:10:07].
Despite their individual successes, these two “arms” of nature—quantum mechanics and relativity—are not compatible; attempts to combine them lead to theoretical “explosions” [02:20:00]. The biggest problem in physics is therefore how to combine the macroscale theory (relativity) with the microscale theory (quantum mechanics) [02:35:48].
Decades of attempts to add quantum corrections to Einstein’s classical theory or to add gravity to quantum mechanics have failed [03:13:00]. According to many scientists, physics strives for unification, combining quantum mechanics with the theory of relativity to create a relativistic theory of quantum mechanics [06:51:00]. Many of the best scientific minds, including Heisenberg and Wolfgang Pauli, tried to combine the mean with the theory of relativity but failed [08:22:00].
String Theory as a Candidate
The leading and currently only theory that could combine both concepts is string theory [02:44:20]. It is a very controversial theory, as its correctness cannot be definitively known or tested [02:54:00]. String theory is currently the only theory that allows for the combination of these two fields [03:41:00] and the only one that has survived these unification attempts [08:35:00].
Concept and Dimensions
String theory is, in simplified terms, a theory of music [05:13:00]. Subatomic particles (like protons, neutrons, and neutrinos) are seen as different vibrations of a tiny string [05:24:00]. Particles are notes created by a vibrating string [05:41:00]. Physics represents the laws of harmony of these vibrating strings [05:46:00]. Chemistry is the theory of the interaction of these strings which form particles and matter [05:53:00]. The universe is a symphony of strings [06:05:00].
An early version of string theory suggested it would only work if space-time had 26 dimensions (one time, 25 space) [04:00:00]. Later, better versions proposed 10 or 11 dimensions [04:25:00]. String theory is the only scientific theory that dictates its own dimensions, unlike Newton’s laws which can exist in any number of dimensions [13:10:00]. For string theory to be stable, it requires 10 or 11 dimensions [13:00:00]. This theory suggests the Big Bang occurred in 11 dimensions, not as an ordinary three-dimensional explosion [13:41:00].
Limitations and Implications
String theory cannot be tested because it speaks of particles whose energy far exceeds what can be produced on Earth; humanity is currently too primitive to investigate it [07:13:00]. Despite its controversial nature and current lack of empirical evidence, there is no competing theory as sophisticated as string theory [05:02:00].
String theory is not just a theory of electrons, protons, and neutrons; it is a theory of music with notes higher than these particles [15:43:00]. Most of the universe is composed of dark matter, which string theory is developed enough to explain as another “octave” of the string [16:07:00].
Stability of Matter
A key implication of quantum mechanics is the stability of matter and the possibility of life. Without quantum mechanics, atoms would fall apart [03:16:00]. In classical Newtonian physics, solar systems would collide and scatter planets, leading to an unstable universe [03:48:00]. Quantum mechanics creates waves of stability, allowing for the formation of stable atoms and huge particles like DNA, which are building blocks of organisms [31:04:00]. Photosynthesis and life itself would be impossible in a purely classical world [31:19:00]. Humanity is a “by-product” of quantum mechanics; without it, everything would fall apart into a fog of subatomic particles [32:04:00].
Consciousness and Quantum Mechanics
The exact structure of the brain and the nature of human consciousness remain a great mystery [33:47:00]. While some believe ordinary mechanics can explain the brain through transistors and circuits, there’s a possibility that quantum mechanics also plays a role, particularly in relation to free will [34:03:00].
Free will is defined as the ability to be independent and creative, without external commands or a prepared scenario [34:15:00]. Robots, being mechanical and deterministic, do not possess free will [34:32:00]. If human consciousness is not merely calculations, then artificial intelligence with true consciousness may never be created [34:47:00]. Quantum mechanics introduces uncertainty, which allows for creativity, thinking, and consciousness [35:28:00]. Therefore, consciousness could be a by-product of quantum mechanics [35:35:00].
The concept developed by Stuart Hameroff and Roger Penrose concerning microtubules suggests that a quantum element is needed for consciousness, stemming from the “collapse of the wave function,” a physical process not fully understood [35:43:00]. The argument for free will questions whether it arises from this part of quantum mechanics [36:13:00]. While there is no single theory of consciousness, it is thought that a machine capable of knowing and understanding its location in the universe and interacting with humans might be possible [36:31:00].