What is considered substantial evidence in the context of the definition of the word "substantial evidence"?

" 'Substantial evidence' is evidence of ponderable legal significance, evidence that is reasonable, credible and of solid value. [Citation] . . . Inferences may constitute substantial evidence, but they must be the product of logic and reason. Speculation or conjecture alone is not substantial evidence. [Citations.] [] . . . [] The ultimate test is whether it is reasonable for a trier of fact to make the ruling in question in light of the whole record. [Citation.]" (Roddenberry v. Roddenberry (1996) 44 Cal.App.4th 634, 651-652.)