You mean, like the fact of Earth-centric solar system models everybody used to believe in?

This is not why people look down on philosophy. This is why STEM people fail to learn anything about it. Other people look down on philosophy, because it's close to impossible to make a living out of philosophy.

The fact that science changes and people used to disagree is a testament to the difference between the two fields. Testability is where science gets it's credibility so it's not surprising that it doesn't have much credibility among scientists. How many times has philosophy made a prediction about how things worked that was observable? I'm not saying it should have the reputation it does but it doesn't surprise me at all.

Philosophy is not predictive. Why do people think that? Is set theory predictive? The very principle that you describe, the principle of falsifiability of a scientific theory, is a philosophical construct (developed and described by Karl Popper) on which today's scientific approach is based.

There are lots of facts gained from philosophy. The issue is that any subset of philosophy that produces useful results gets developed into its own field of knowledge. Thus, what is classified only under philosophy is a dead sea effect of sorts, resulting in the low opinion of philosophy.

One neat result in metaphysics is the discovery that there can't be a property for every predicate, since this gives rise to analogs of Russel's paradox. (Does the property of being a non-self-exemplifying property exemplify itself?)

This is a result in logic, a branch of mathematics. Logic, as practiced inside mathematics, is far more advanced than what's practiced inside philosophy departments. Something like more than 95% logic professors inside philosophy departments cannot competently explain anything in logic after Godel & Tarski.

It seems to me that there is no clear break between logic and philosophy?

Nor between logic and mathematics.

There is also the idea that part of why philosophy is dismissed is because people tend to take results and say that the result isn't really part of philosophy.

Could this be because their idea of philosophy is that it has no results, so any results they are shown are concluded to be not part of philosophy?

It's not a result in logic. The question of which properties (if any) exist is not a logical question but a metaphysical one.

Of course, philosophers often make use of results in mathematics. If you arbitrarily decide that any philosophical work that does this in some sense "doesn't count", then of course you will find that the remaining work concerns results that are less than certain! It's in the nature of questions that can't be answered through mathematical methods to have less than certain answers. You might notice that many of the most important questions in life fall into this category, though.

Contractions don't prove philosophical arguments. They only demonstrate something is inconsistent, but nothing requires reality or systems of thought to be consistent.

This is what separates philosophy from math or logic.

I'm not sure what you mean. If a statement entails a contradiction, then it must be false. So if you can show that the statement "every predicate has a corresponding property" entails a contradiction, then it must not be the case that every predicate has a corresponding property.

In math people are used to A = B has very specific meaning such that B = A. In some systems of thought A=B does not exclude B != A or even A != B.

This might seem ridiculous, how could such a system be useful? Well what about time, just because at one point A=B does not mean A still = B. [Yay, programming ;0]

Now, time is just one specific case, but Philosophy encompasses all systems of thought not just the tiny subset that is western philosophy. Some religions for example actively promote contradictory ideas.

As such, showing contradictions mean more in math suggests something is false, where in philosophy showing a contradiction only demonstrates something is false in a subset of systems of thought.

I haven't really had any philosophy so can you briefly explain what implications this has outside of philosophy? I don't really understand what this means practically

If you want an example of genuinely valuable philosophy, I found "Kinds of Minds" by Daniel Dennett to be a compelling discussion of the origins of consciousness.

It's not "fact" but it does provide interesting ways to think about the issue; ways that could drive experiment or further enquiry. So under a "pragmatic" theory of knowledge I would say that there is information there.

But of course that's a philosophical stance that you should not feel compelled to debate me on ;)

I mean all of physics is open to revision as well right? Should we look down on physics?