So how do we know that they were not simply their own species?

It’s a somewhat hard question to answer for me but maybe that’s because of my ignorance. But I know a few reasons. For one they roamed the same parts of Africa as we did. We know that they did not go extinct that they clearly just evolved because of other fossils found of later evolution of the species.

And to be fair it is it’s own species

But slowly through times it evolved into other species which after many other changes turned into us

That’s a poor wording on how evolution works

theoretically

No

There’s evidence for it

Sure but evidence doesn't mean proof

There’s fossil records that show the link between austrolepithicus and and next evolution

Yes it does

Evidence means proof

Absolutely

You can’t have proof without evidence

If you have evidence of a man who killed someone then that is proof that he is a murderer and he killed someone

Sure an abundance of evidence can lead you to a conclusion

Yes

Absolutely

The only reason you should be lead to a conclusion is from and abundance of evidence

ok....let's say I wear reading glasses

You solve equations from an abundance of evidence to get the answer

Ok

is that evidence that I have eye problems or is it proof?

Both

The glasses are evidence you have an eye problem

it is not proof because maybe I simply like how they look

Ok

So what does that analogy have to do with what I said about evolution

Are the scientists lying about the evidence

Is that what you’re getting at

My point is I guess how do I know that the links referred to in fossil records aren't just another species unrelated but similar in bone structure

it's more about evidence

Because

just because their is an abundance of evidence does mean their is absolute proof

Things are only similar because they are related

We are similar to chimpanzees because we are related

Koala and panda... related?

Yes

Everything is related

whale and shark?

Yes