The problem of how to define experiential qualities is a major problem in empirical psychology. Empirical researchers struggle over what definitions to adopt, what theoretical terms to adopt, what ‘constructs’ can be legitimately ‘applied’ to make sense of, interpret, and study empirical data. Phenomenology shows that empiricism here undermines the legitimacy of psychological experiences by supposing that science must impose arbitrary, nominal definitions upon empirical material, which, by itself, supposedly cannot supply its meaning to us.

But if that is so, then we must ask, from where, how on earth, can we — as scientific observers — obtain ‘definitions’ in order to apply them externally upon the empirical material? Where do definitions come from? This is the sense of Husserl’s claim that phenomenology returns ‘to the things themselves’. Phenomenology claims that things themselves can tell us their intelligibility — or, how their intelligible meaning is constituted in our intuitional experience of them — if we assume the right receptive, intuitive attitude and descriptive method, the phenomenological attitude, to apprehending and describing them.