Though it is rather clear what is meant by a law of causality, it is still difficult to formulate what is to be meant by the law of causality. Let us try, for example, to say: from the state A ₀, of the world at the present moment t ₀,the state A ₁, at each following moment t ₁ is determined unambiguously. This can mean two different things; either, as often as the world assumes the state A ₀ it will, after the time (t ₁ - t ₀), assume the state A ₁, or we could say, there is a law which, for each state A ₀ at time t ₀, allows us to compute state A ₁ at the time t ₁, if t ₁, is greater than t ₀.