Multiverse And The Time Patrol

Greg Bear and Gardner Dozois, Editors, Multiverse: Exploring Poul Anderson's Worlds (Burton, MI, 2014).

Three stories in Multiverse refer to the Time Patrol:

"A Slip in Time" by SM Stirling;
""Christmas in Gondwanaland" by Robert Silverberg;
"The Far End" by Larry Niven.

I partially discussed these stories in my first three posts about this new anthology. Of the three:

Stirling's is closest to being an authentic continuation, although I noted some differences from Anderson's approach;
Niven's is in Niven's style and, I think, is set in a different universe where there just happen to be beings called Danellians and an organization called the Time Patrol;
I have some problems with the time travel logic of all three stories and, so far, this has prevented me from continuing to read Silverberg's.

Any time travel story raises the questions:

Is the story internally consistent?
Does its plot follow from or contradict its premises?

If the story addresses the circular causality paradox, then it can be fully consistent. I have cited examples on the Logic of Time Travel blog. (See here.) If instead the story addresses the causality violation paradox, then life is more difficult. The first problem is that the most fundamental premises of the Time Patrol series are, first, that causality can be violated and, secondly, that an organization is necessary to prevent this from happening. Throughout history, behind the scenes, professionals equipped with far future technologies and weapons labor tirelessly to ensure that Socrates is executed in 399 BC, that William of Normandy conquers England in 1066 AD, that World War I begins in 1914 etc.

The second problem is that Anderson's rationale for this scenario is subtle and distinctive. New writers have two problems: how to maintain their own internal consistency and also how to remain consistent with what Anderson wrote. When thinking about the Patrol, we have to get used to thinking about alternative timelines and about how these timelines relate to each other. The question of whether and in what sense these timelines exist or are real is important but can sometimes be sidelined while we focus on their relationships. Thus,  "Delenda Est" presents three successive timelines:

a timeline without a particular Neldorian intervention;
a timeline with that intervention;
a timeline with the Neldorian intervention but also a Patrol counter-intervention.

I call these timelines "successive" because there is between them a temporal relationship of before and after, of first, second and third, and even of cause and effect.

Silverberg introduces the idea that the Patrol was founded at a conference way back on the original single continent, Gondwanaland. Alright so far but what happens next? Imagine two timelines:

(i) the familiar timeline guarded by the Patrol;
(ii) an alternative timeline in which every human being at that conference was assassinated while in Gondwanaland so that no Patrol was ever founded.

How can Time Patrolman Everard travel from the twentieth century of (i) to the Gondwanaland of (ii)? According to Anderson, he must travel back along (i) until a time before the assassinations, then forwards into (ii). According to Silverberg, he can jump directly from twentieth century (i) to Gondwanaland (ii). That is certainly inconsistent with Anderson and I cannot see that it is internally coherent either.