Ipse dixit literally means he himself said it. It is a bare assertion resting on the authority of an evidence resting on the statement or assertion of the person who made it. It is an evidence not substantiated. See Busari V. Adepoju (2017) All FWLR (Pt. 878) 508.
An evidence given “ipse dixit” is not inadmissible in evidence even though it is an evidence resting on the assertion of the one who made it. Where however the person who made the assertion denies, there is need for further proof, a mere “ipse dixit” may not be enough to qualify as admissible evidence. This is because such evidence in need of further proof needs to be substantiated by some other corroborating evidence. when it is not substantiated it remains in the realm of assertion and cannot be regarded as credible evidence worthy of belief. See Busari V. Adepoju (2017) All FWLR (Pt. 878) 508.
“Ipse dixit” evidence though admissible needs further proof. That is for “ipse dixit” evidence to be admissible in evidence, it has to be substantiated. The quantum of proof required is corroboration by other evidence apart from the bare assertion of the witness giving it. However, if the evidence is unchallenged minimum proof will be needed. Busari V. Adepoju (2017) All FWLR (Pt. 878) 510.