If someone sues another person over a claimed infringement of Texas' new professedly anti-abortion bill, what standard of evidence is used? The bill itself calls its enforcement provision a "civil liability". Does that mean the claim needs to be proven beyond reasonable doubt, as it would in a criminal trial, or will the court look at the preponderance of the evidence as in most other trials about a civil liability?
The standard of proof for civil cases in Texas is generally "preponderance of evidence". See in re Steven Lipsky for some discussion.
The applicable evidentiary standard is generally determined by the nature of the case or particular claim. Criminal cases require proof beyond a reasonable doubt, a near certainty, whereas civil cases typically apply the preponderance-of-the-evidence standard, that is, a fact-finder’s determination that the plaintiff’s version of the events is more likely than not true. Some civil claims, including some defamation claims, elevate the evidentiary standard to require proof by clear- and-convincing evidence.
See Sec. 171.208 of SB8. There is no specific statutory specification of the evidentiary standard, therefore the standard is "preponderance of evidence" (compare Lipsky: the issue is that the statute refers to "clear and specific evidence" which is not defines in the statute or elsewhere, hence that lawsuit).