The opponent might say that the effect need not pre-exist in the material cause because when the cause is potent even a non-existent effect can be made to exist by the causal operation. When, on the other hand, the cause lacks the potency the desired effect cannot be produced. Since oil-seeds possess the adequate potency, oil can be produced out of these seeds but not out of sand. Sāṃkhya philosophers concede this point and maintain that causal operation enables a potent cause to manifest the latent effect. However, they point out that positing potency or efficiency will not satisfy their opponents. For then the question will be: where does this potency exist? The opponent must agree that this potency exists in the material cause. Does this potency have any relation with the effect or not? The answer has to be affirmative, otherwise we would not have said that oilseeds possess the capacity of producing oil and not pots. So once again we are back to the same question: how can the potency residing in the material cause be related with a non-existent effect? The Sāṃkhyas, therefore, affirm that this causal efficiency is nothing other than the existence of the effect in the material cause in a latent form.