Where does secular collide?

Edmond Halley suggested in 1695, from comparing ancient eclipse records with the observations of his own day, that the Moon's average motion was slowly speeding up, a change that does not repeat with each orbit or each year but builds up steadily across centuries (Halley, 1695; first measured by Dunthorne, 1749). In celestial mechanics a change of this kind is called secular: the part of a body's motion that grows in one direction without turning back, as opposed to the periodic wobbles that cancel out over a single orbit, and later gravitational analysis traced it to the slow pull of the other bodies (Murray and Dermott, 1999). Here the word points to a long-run drift in a physical orbit, timed against the clockwork of the sky, and it has nothing to do with religion fading in a society or with church property passing to the state.[1][2][3]

Unit

A rate of orbital change, for example arcseconds of drift per century

Recovery means

Not applicable; the change accumulates in one direction and does not reverse over an orbit

Measured by

Found by comparing positions across long baselines of observation and modelling the gravitational perturbations

Bryan Wilson's 1966 Religion in Secular Society and Peter Berger's 1967 The Sacred Canopy set out the modern thesis that as societies modernise, religion loses its hold over public life, shared belief, and institutions, an idea with roots in the earlier sociology of Weber and Durkheim. Chaves (1994) sharpened it into a decline in the authority of religious organisations rather than simply a fall in the number of believers. In this meaning the word names a gradual social process tracked across a whole population over decades, and it is unrelated to a slow drift in an orbit or to the one-time legal transfer of church holdings to civil hands.[4][5][6]

Unit

A trend in religion's influence over a population, across decades

Recovery means

Not applicable; whether the trend can reverse is debated

Measured by

Operationalised through rates of attendance, affiliation, and belief, and through measures of religious institutions' authority

In its original use the word named a concrete legal act: converting property, personnel, or jurisdiction from religious to civil control, as when monasteries were dissolved and their lands passed to the crown. Shiner's 1967 review of how researchers use secularization set out this transfer from religious to secular hands as one distinct meaning of the term, and Casanova (1994) traces the usage back to canon law, where a priest could be moved from monastic to secular standing. Here the word marks a specific handover of holdings or status to the worldly domain, a legal event with a date, and it is neither a slow orbital drift nor the broad decline of religion's grip on a society.[7][8]

Unit

A specific transfer of church property, personnel, or jurisdiction to civil control

Recovery means

Not applicable

Measured by

Identified case by case through legal and historical records of specific transfers