Does the Light spell cast by a 5th level caster overcome the Darkness spell?

Question

The Darkness spell says:

This also suppresses magical light of your darkness spell's level or lower.

Assuming it isn't heightened, this means Darkness is a 2nd level spell.

The rules for Cantrips say:

A cantrip is always automatically heightened to half your level, rounded up.

The rules for Heightened Spells say:

When you heighten your spell, the spell’s level increases to match the higher level of the spell slot you’ve prepared it in or used to cast it.

So a 5th level caster casting Light would cast it heightened to 3rd level, meaning it counts as a 3rd level spell.

Is this to say that a 5th level caster can counteract Darkness (at its base level) with a cantrip?

Answer 1

Yes

You already cite all the relevant rules.

Maybe you are wondering if it is appropriate that a simple cantrip, cast by a high-enough level caster, will overcome a leveled spell. Narratively you can look at it this way: with the rule of automatically heightening their spell level, the design of cantrips in PF2E has them also be an expression of the caster's power, and it is that power that overcomes the spell.

Answer 2

Yes, but not by counteracting.

The light cantrip has the light trait, which says specifically:

You must usually target darkness magic with your light magic directly to counteract the darkness, but some light spells automatically attempt to counteract darkness.

Since light targets an object, it cannot directly target the darkness spell, and, since there is nothing in the light cantrip to suggest that it always attempts to counteract darkness around it, it does not. Of course, a GM may allow you to cast light or darkness in such a way as to counteract the other effect.

However, the bright light and dim light produced by the light cantrip are not suppressed*, so the effect of the darkness spell in this case is entirely negated where the two effect areas overlap. (NB: darkness does not explicitly attempt to counteract light effects either - a suppressed effect will resume once the darkness has ended or the suppressed effect has left the darkness area)