Psychologists used to talk about perfectionism as though it were unidimensional — only directed from the self to the self. That’s still the colloquial usage, what we usually mean when we say someone’s a perfectionist. But in the last few decades, researchers have found it productive to broaden the concept. Curran and Hall rely on a multidimensional definition, encompassing three types of perfectionism: self-oriented, other-oriented, socially prescribed. Self-oriented perfectionism is the tendency to hold oneself to an unrealistically high standard, while other-oriented perfectionism means having unrealistic expectations of others. But “socially prescribed perfectionism is the most debilitating of the three dimensions of perfectionism,” Curran and Hall contend.

Expressed in the most general terms, the Heisenberg effect refers to those research occasions in which the very act of measurement or observation directly alters the phenomenon under investigation. Although most sciences assume that the properties of an entity can be assessed without changing the nature of that entity with respect to those assessed properties, the idea of the Heisenberg effect suggests that this assumption is often violated. In a sense, to measure or observe instantaneously renders the corresponding measurement or observation obsolete. Because reality is not separable from the observer, the process of doing science contaminates reality.

For example, if a philosophical zombie was poked with a sharp object it would not feel any pain sensation, yet could behave exactly as if it does feel pain (it may say "ouch", recoil from the stimulus, and say that it is feeling pain).