I generally consider redundancy to be applicable to the safety factors (load bearing capacity) not the particulars of the construction.

In engineering (and many other fields) safety factor and redundancy are different things and have to be evaluated differently. For example the commercial aircraft you fly in uses safety factors for the airframe but redundancy for the propulsion system and the pilot.
A useful paper on the logic behind the two systems is http://www.umowlai.com.au/uploads/Cliffhanger.pdf which is reasonably understandable.
A sliding X with limiters is partly redundant (if the sling fails between the limiter knots you die), two draws are completely redundant. Two draws is considerably stronger and therefore has a higher safety factor. I´d prefer the system with a higher safety factor and complete redundancy myself!

You have a basic but common misunderstanding of the meaning of "redundancy" in climbing.

Anyone with half a brain and has been climbing longer than a few days knows that none of these definitions apply to how the term is used in the technical climbing domain.

What did you mean in your initial post? What is the OP's basic and common misunderstanding?

Don't forget the final days of rec.climbing and rec.alpineskiing - those are both pretty high bars to clear.

You {UpToTheOzon} have a basic but common misunderstanding of the meaning of "redundancy" in climbing.

Anyone with half a brain and has been climbing longer than a few days knows that none of these definitions apply to how the term is used in the technical climbing domain.

One of the things I wish the anchor books would do is to help new climbers begin to think more critically and constructively about safety issues......

This is something that is causing me a few problems in an article I´m (very slowly) writing, working out how one recognises the optimum strategy or at least avoids the worst one. The problem is mostly the technical aspects (equalisation, shock loading, load shift and so on) aren´t as clear cut as they could be so it´s hard to really say x is better than y, there are so many qualifiers added that it all ends up a bit muddled.
I´m tending towards strategies that perform at say 90% all the time instead of 100% some of the time combined with simple systems that have proved reliable over the years, the trouble being this all sounds too basic for the modern generation who want to learn from books and videos and have trouble with the concept of just getting loads of gear and tying it all together somehow.
I´ll just have to dress it all up with some cool sounding phrases so it´s trendy I guess!

A sliding X with limiters is partly redundant (if the sling fails between the limiter knots you die), two draws are completely redundant. Two draws is considerably stronger and therefore has a higher safety factor. I´d prefer the system with a higher safety factor and complete redundancy myself!

This is something that is causing me a few problems in an article I´m (very slowly) writing, working out how one recognises the optimum strategy or at least avoids the worst one.

i wasnt aware that i needed to be a math expert to build an 2 bolt TR anchor

thats weird ... i havent come across any 2 bolts anchors that you couldnt just use a sling and tie off with a fig 8 yet, with padding if needed ...

i wasnt aware that i needed to be a math expert to build an 2 bolt TR anchor

The following may or may not be helpful in the specific cases you deal with in your article, but I've found it to be helpful to me in explaining things to other climbers: 1 - Categorize the situation first by identifying the most dangerous aspects to it. And then 2 - Look for a solution to the situation that puts the highest priority on mitigating the most serious dangers.

For example, in the dual case I took before: In the first case, the most serious danger for the lead climber with the two RP placements is that both of them will fail, and she will take a long and dangerous fall. And the best way to mitigate that risk is by equalizing those placements. Then, in the second case, the most serious danger for the toproper is that a line running over the edge may get worn through or cut on an unnoticed sharp crystal, dropping the climber until the other line catches her. And the best way to mitigate that risk is to have two independent lines running over the edge, with a static knot tied at the power-point.

Does that make sense? Does it help at all?

GO

In engineering (and many other fields) safety factor and redundancy are different things and have to be evaluated differently. For example the commercial aircraft you fly in uses safety factors for the airframe but redundancy for the propulsion system and the pilot.
A useful paper on the logic behind the two systems is http://www.umowlai.com.au/uploads/Cliffhanger.pdf which is reasonably understandable.
A sliding X with limiters is partly redundant (if the sling fails between the limiter knots you die), two draws are completely redundant. Two draws is considerably stronger and therefore has a higher safety factor. I´d prefer the system with a higher safety factor and complete redundancy myself!

It's not clear to me that two draws are redundant and that the sliding X with limiter knots is not. The sliding x has two strands in the center, both of which must fail (or along with something else) for catastrophic failure. While I would concede that the likelihood of both strands of the sliding x failing at the same time are probably significantly more likely than both biners in a two draw situation failing simultaneously, I think both have some probability and therefore are not categorically different; only different in their likelihood.

I can understand the difference between safety factors and redundancy but it seems that some things (i.e. airframes, harnesses, etc.) are not feasibly made redundant so other safety measures are taken in their case.

In the end, I'd rather have two draws on a (straight forward) two bolt anchor.

I think this falls into general decision making processes which can, to some degree, be taught but in order to do it well you need a broad base of understanding of the subject matter you're dealing with.

For instance, one of the early steps of the military decision making process is to try to understand your enemy. Staffs generally try to identify the most likely, as well as the most dangerous, enemy course of action and, when developing friendly courses of action endeavor to effectively counter both of these potential outcomes in their solution. However, without a good base of experience to apply to the situation you're likely to have some big holes in your plan.

The most effective method to train decision making that I have seen is through example and "hands on" experience with few shortcuts (especially for those who don't learn well from others' mistakes).