All new appearances had previous existence

Samkhya postulate: The potential to bring about an effect exists in the cause.

When we are aware of something which begins to be, we are by the necessity of our intelligence, constrained to believe that it has a cause. But what does the expression, that it has a cause, signify? If we analyse our thought, we shall find that it simply means, that as we cannot conceive any new existence to commence, therefore, all that now is seen to arise under a new appearance had previously an existence under a prior form. We are utterly unable to realise in thought the possibility of the complement of existence either increased or diminished. We are unable on the one hand, to conceive nothing becoming something
or on the other something becoming nothing. There is thus conceived an absolute tautology between the effect and its causes. We think the causes to contain all that is contained in the effect; the effect to contain nothing which was not contained in the causes.

Sir William Hamilton, Lectures on Metaphysics XXXIX