What is the standard of proof applicable to future, hypothetical or contingent events?

It is important to emphasize the fundamental distinction that this excerpt draws between the requisite standard of proof for past events and the standard of proof applicable to future, hypothetical or contingent events. In Athey v. Leonati, Major, J., cites the above excerpt from Lord Diplock’s speech and then describes the different standards in the following words at paras. 27‑28: Hypothetical events (such as how the plaintiff’s life would have proceeded without the tortious injury) or future events need not be proven on a balance of probabilities. Instead, they are simply given weight according to their relative likelihood: . . . A future or hypothetical possibility will be taken into consideration as long as it is a real and substantial possibility and not mere speculation: . . . By contrast, past events must be proven, and once proven they are treated as certainties. In a negligence action, the court must declare whether the defendant was negligent, and that conclusion cannot be couched in terms of probabilities. . . .