Where does expression collide?

The process by which the information encoded in a gene is used to build a functional product, chiefly RNA and then protein: a gene is transcribed into messenger RNA, and that message is translated into a polypeptide, so the amount and timing of this output is what is meant by a gene being expressed. Crick's 1970 Central dogma of molecular biology set out the permitted directions of this information transfer, from DNA to RNA to protein. The referent is a biochemical process inside a cell, measured as transcript and protein abundance, and it is not a symbol that evaluates to a value, a face that shows a feeling, or feeling conveyed in a work of art.[1]

Unit

A gene's output of RNA and protein, by transcript and protein abundance

Recovery means

A gene can be silenced and later re-expressed as regulatory signals change, so the level is not fixed

Measured by

Quantified by RNA sequencing, microarray, or quantitative PCR for transcripts, and by proteomic assays for protein levels

In a formal language, an expression is a finite string of symbols, built by the grammar's rules from constants, variables, and operators, that denotes a value under an agreed interpretation: evaluating the expression yields that value. Kleene's 1956 Representation of events in nerve nets and finite automata introduced regular expressions, expressions whose value is a set of strings, and showed they describe exactly the events a finite automaton can recognise. The referent is a syntactic object in a formal system, checked by its grammar and by the value it denotes, and it has nothing to do with a gene's output, a facial display of emotion, or feeling voiced in art.[2]

Unit

A well-formed symbolic term and the value it denotes under an interpretation

Recovery means

Not applicable

Measured by

Checked by parsing against the language's grammar and by evaluating the term to the value it denotes

The outward display of an internal affective state, especially through the face, but also the voice and posture: an emotion felt inside is shown on the outside, where an observer can read it. Ekman and Friesen's 1971 Constants across cultures in the face and emotion found that certain facial expressions of emotion were recognised across widely separated cultures, evidence that some expressions are not purely learned. The referent is an observable behavioural signal of feeling, coded from the face and body, and it is not a gene's biochemical output, a symbol that evaluates to a value, or the aesthetic quality of a work.[3]

Unit

An outward, readable signal of an inner affective state, from face, voice, or posture

Recovery means

Not applicable

Measured by

Coded from the face by systems such as the Facial Action Coding System, and rated by trained observers for the emotion displayed

In aesthetics, expression is the conveying of feeling in a work of art: the artist gives form to an emotion so that the work carries or embodies it, and the audience apprehends that feeling through the work. Collingwood's 1938 The principles of art argued that art proper is the expression of emotion, an activity in which the artist clarifies a feeling by giving it form, distinct from merely arousing or describing it. The referent is an aesthetic relation between a work and the feeling it conveys, appraised by critical judgement, and it is not a biochemical process, a symbolic term, or a face read for its emotion.[4]

Unit

The feeling a work conveys or embodies, and how fully its form carries it

Recovery means

Not applicable

Measured by

Appraised by critical and interpretive judgement of how the work conveys feeling, not by a numeric scale