Does philosophy make progress?
What have philosophers discovered?
Which objective facts has philosophy taught us?
One might challenge the underlying rationale behind these questions. After all, philosophy is extremely valuable even if it doesn't make progress. Its value is in making us better people. However, I think it's also arguably valuable in the progress that it makes.
Some philosophers will disagree with some of this. Therefore, what follows is my opinion.
It's possible to put together at least a partial list of known philosophical truths.
You won't discuss these much in a philosophy course because most of us already know these, and they're not widely-disputed. When we teach people philosophy, we teach them the method as well, which is much easier when we teach the topics that are more controversial. That's one reason that some students sometimes feel that philosophy doesn't make much progress.
These facts are objective because if someone disagrees with them, that person is just incorrect. (That's how philosophers primarily use the term 'objective.') There may be exceptions, in extreme cases, to these generalizations, but that doesn't mean that the statements of the facts are false, in the same way that if someone says 'humans live on Earth,' that doesn't mean that no human has ever been to the moon.
A Partial List of Known Philosophical Truths
Epistemology, Metaphysics, and Language
- We are justified, in general, in trusting our senses.
- We are justified in trusting logic and reason.
- There is a mind-independent external world.
- A sentence can be meaningful even if we do not know how it could be empirically verified.
- There is no undeniable proof of the existence of the God of any major religion.
- It is possible to be morally good without believing in God or gods.
- Happiness is good and suffering is bad.
- Justice is good and injustice is bad.
- Murder, rape, and other assault are morally wrong.
- Slavery and genocide are morally wrong.
- Torture is morally wrong.
- Sentient animals should not be harmed without a very good reason.
Social and Political Philosophy
- If a government regularly and severely violates the rights of its citizens, then the citizens are morally permitted to rebel.
- Citizens are not morally obligated to obey dictators.
- No one should be disadvantaged or subordinated because of his or her gender or sex.
- People should have equal legal rights regardless of race.
- People should not have freedoms taken away without a very good reason.
Are these really "philosophical" facts? Aren't they just obvious truths?
They are obvious truths. But they concern philosophical topics, such as justification, value, and allegedly non-physical entities.
Philosophical truths are often obvious, but obviousness is a characteristically philosophical way of learning.
Some people disagree with some of these facts. But that doesn't mean that they're not known philosophical truths. Other known truths (e.g. evolution, global climate change) inspire disagreement.
Even some philosophers disagree with some of these truths. But those philosophers are wrong. It's possible to show this, but not in this forum. (If you take a philosophy course, you'll probably see how.)