I always understand entanglement as &#x27;cannot be factored&#x27;. It&#x27;s really just that mathematical and simple.<p>Say there are particles a and b that can be in states 1 or 2<p>entangled: a1 * b2 - a2 * b1, vs
not entangled: (a1+a2)*(b1+b2)<p>So, when you apply a measurement operator on the state of particle a, you know something about particle b in the entangled case.<p>Schrodinger said: &quot;the best possible knowledge of the whole doesn&#x27;t necessarily include the best possible knowledge of the parts.&quot; An entangled state should be treated as a whole, and not a sum of parts, kind of like how a book is treated as a continuous story, not a sum of letters.