Water doubled, and fixed
Both take a situation seriously and neither disperses a feeling. What is felt here stays felt, at strength, for as long as the situation warrants and often considerably longer.
Sharing that removes an ordinary and useful annoyance: neither has to defend the intensity or apologise for the length of a mood. What it also removes is anyone in the room able to say that a thing has been carried long enough, which is the specific cost of doubling this sign, and it applies to grudges as much as to grief.
Fixed on fixed
Nothing here yields. Two fixed signs in disagreement do not negotiate towards a middle; they hold, and wait, and the matter is settled by whichever of them finds the impasse less tolerable.
That produces standoffs of unusual duration. Because Scorpio also declines to state the terms, the other party is frequently holding out against a position it has had to infer. Disputes here are long, quiet and expensive, and outside observers often do not notice one is happening. The pairing looks composed from outside for the entire duration.
Mars and Pluto, on both sides
Traditional practice gives Scorpio to Mars and modern practice to Pluto, so both bodies sit behind both people. Mars supplies strategy and a very long memory for who did what; Pluto supplies the drive to get underneath the official account.
With that configuration doubled, each is investigating the other. Where Mars and Pluto actually fall in the two charts decides whether that reads as attentiveness or as surveillance, and the difference between those is not small. A softer Venus in either chart does a good deal to keep it on the first side.
What neither supplies
Lightness. Neither will be the one to treat something as unimportant, so nothing gets defused from inside, and a bad period has no natural end point.
The other absence is disclosure. Both withhold on the reasonable principle that information given away cannot be recovered, and both read the other's withholding correctly, which confirms the policy. Trust in this pairing has to be built deliberately, because the default behaviour of both parties works against it.
Why identical Suns decide little
A shared sun sign means a shared temperament in one respect only. The sign covers a twelfth of everyone alive, and two people born under it can differ enormously in what they need and how they behave.
The Moon governs what each requires in private, Venus how affection is offered, Mars how conflict is conducted. Two Scorpio Suns with well-aspected Moons live very differently from two whose Moons are at odds. No page organised by sun sign can tell you which of those you are in.
Questions people ask about this
Do two Scorpios understand each other?
Immediately, and that is not the same as trusting each other. Both recognise the withholding because both do it.
Why do arguments last so long here?
Neither sign concedes and neither states its terms plainly. The standoff continues until one party finds it less bearable than the alternative.
Is the doubled intensity a problem?
It removes the need to explain oneself and removes any source of lightness. Nothing in the pairing defuses a bad stretch from the inside.
Does sharing a sun sign mean similarity?
Only in one respect. The Moon, Venus and Mars vary freely between two people with the same Sun and usually matter more.