Traditionally, the proposed laws of love have fallen into two categories: psychological laws, which establish regularities in love as a feeling, and moral laws, which impose discipline on love to render it moral or just.

A striking example of a psychological law of love appears in Tacitus’s words: Omne ignorum pro magnifico ¹, which translates to: 'Everything we do not know is considered magnificent'. This suggests a law of love akin to, 'We love what we do not know'. Ovid contrasts this with his famous phrase, Ignoti nulla cupido ², meaning 'You do not desire what you do not know'.

In Saint Augustine, however, we find a conception closely aligned with the idea of a moral law of love. Augustine distinguishes between two kinds of love in passages that intersect with the contrast between the two cities—earthly and Christian—in The City of God: These two loves, of which one is holy, the other unclean, one social, the other private, one taking thought for the common good because of the companionship in the upper regions, the other putting even what is common at its own personal disposal because of its lordly arrogance; one of them God’s subject, the other his rival; one of them calm, the other turbulent; one peaceable, the other rebellious… ³.

This leads Augustine to define virtue as a particular kind of love—one rightly directed toward order: The brief and true definition of virtue is the love of order ⁴. Here, we observe a discipline to which love must submit, forming a kind of ‘canon’ that enables us to evaluate the worth of a particular love.

My aim, however, is to uncover something fundamentally distinct from these traditional laws of love.

Three examples from literature and philosophy illustrate what I mean by the essential condition of love:

First, Shakespeare:
Let me not to the marriage of true monds
Admit impediments ; love is not love
Which alters when it alteration finds
Or bends with the remover to remove.
O no, it is an ever-fixed mark
That looks on tempests an dis never shaken ⁵

To summarise: love is not true love if it changes when its object changes, or if, when rejected, it in turn rejects its object.

1. The Agricola
2. The Art of Love
3. The Literal Meaning of Genesis, XI, 14, 19-15, 20
4. City of God, XV, 22
5. Sonnet 116