[blamestross]

We have long passed at least my owner personal "threshold of evidence" to assume that Mars had life.

That bar is pretty low. I am not hard to convince.

We don't have a baseline by which to contextualize the situation statistically. There is no p-value we can meaningfully satisfy. Worse than that, evidence required for a belief derives from the risk of being wrong.

Is there a discussion of what evidence WOULD be enough for the scientific community to say loudly "There was life on mars". Because right now it seems all risk and no utility, so the evidence bar would be really high.

[raychis]

The bar for scientific discoveries is generally incredibly high and rightly so. In particle physics for example for a discovery to be confirmed it must be independently verified by a second experiment and both the discovering experiment and confirming experiment must be within five standard deviations (or a roughly 1 in 3.5 million) chance of not being a discovery. Its not a perfect comparison because astrobiology is messier but it is useful to see how high the bar is.

For a discovery of the magnitude of life outside our planet the scientific community would probably need something like: a real and well-characterised signal, multiple independent lines of evidence, strong geological context, replication by independent teams, and a serious failure of plausible alternate explanations. Until then, “potential biosignature” is probably the right phrase.

To be clear, I think like you that there probably was life at some point on Mars. I am pretty convinced. But, you and I being pretty convinced does not come close to the threshold of a scientific discovery.

[microgpt]

We can say we discovered signs there might've once been life on Mars