Final answer:
Quantum principles seem alien because they contradict our classical, macroscopic understanding of the world, featuring phenomena like superposition, the Heisenberg Uncertainty Principle, and wave-particle duality, all of which challenge intuitive notions of how particles behave.
Step-by-step explanation:
Quantum principles seem alien because they fundamentally challenge our classical understanding of physics. In the realm of quantum mechanics, particles can exist in multiple states simultaneously, a phenomenon known as superposition. This starkly contrasts with the macroscopic world, where objects have definite positions and velocities. The Heisenberg Uncertainty Principle further defies intuition by stating that one cannot simultaneously know the exact position and velocity of a particle, which undermines the determinism of classical mechanics.
The strangeness continues with the concept of wave-particle duality, where particles like electrons exhibit both wave and particle characteristics, depending on the experimental setup. This leads to the 'observer effect,' where the act of measuring can influence the observed property. Such principles are difficult to reconcile with everyday experience, gaining labels like 'weird' and 'bizarre'. Even famed physicists like Niels Bohr and Richard Feynman acknowledged the counterintuitive nature of quantum theory, with Feynman remarking on the general lack of understanding of the theory despite its vast applications.
Ultimately, the alien nature of quantum principles stems from their significant departures from the predictable, tangible behaviors observed in the macroscopic world that humans interact with daily.