Whether various types of theoretical and applied hard sciences are sufficiently scientific and reliable to satisfy the requirements for admissibility under Federal Rule of Evidence 702 or a comparable State rule

Fed. R. Evid. 608(b) (specific instances of the conduct of a witness "if probative of truthfulness or untruthfulness" may be inquired into during the cross-examination of the witness).Prior acts of a witness may be elicited during the interrogation of the witness to impeach the truthfulness of a witness, but the acts so inquired into must in fact be probative of truthfulness.

United States v. Ettinger, 344 F.3d 1149, 1160-1161 (11th Cir. 2003) (upholding trial court's admission of officer Barnes' statement contained in the FBI report because "the FBI report was admissible as a prior consistent....A prior statement of a witness is exempt from the prohibition against hearsay evidence if the prior statement is consistent with the witness' testimony at the trial or hearing at which the prior statement is offered, the prior statement is offered to rebut a express or implied charge of recent fabrication or motive, and the witness who made the prior statement testifies and is subject to cross-examination at the trial or hearing at which the prior statement is offered.

United States v. Hill, 40 F.3d 164, 169 (7th Cir. 1994) (upholding trial court's exclusion of 'test letters' evidence which was allegedly probative of accused's character trait for law-abidingness because the proper method of proof would have been by reputation or opinion testimony).When an exception to the character evidence prohibition makes evidence of a criminal defedant's character admissible, the testimony of a witness on direct examination about the defendant's character must take the form of reputation or opinion and it cannot consist of specific instances of the defendant's conduct.