  Given Aristotle's observation (Metaphysics 1006a2) that “even some physicists” deny LNC and affirm that it is indeed possible for the same thing to be and not to be at the same time and in the same respect, he might not have been surprised to learn that quantum mechanics has brought such challenges once more into play. Thus, we have Schrödinger's celebrated imaginary cat, placed (within the context of a thought experiment) inside a sealed box along with radioactive material and a vial of poison gas that will be released if and only if that material decays. Given quantum uncertainty, an atom potentially inhabits both states—decayed and non-—simultaneously, seeming to render the cat (in the absence of an observer outside the system) both alive and dead. But most physicists would argue that while quantum mechanics may challenge some aspects of classical logic it does not threaten LNC. If we could in fact observe a cat, or a particle, as A and not-A at the same time, then there would be a violation of the Law of Non-Contradiction; the mere potential for an entity to be in either of two mutually inconsistent states does not in itself violate the LNC.  