bodies are either simple or composite. If they are simple, whatever is possible for one side is possible for the other. Their right side can therefore become their left, and their left side their right; hence, motion is possible for them. If they are composite, they consist of simple bodies joined together. Those simple bodies can therefore come together and separate, and thus are capable of motion. This is a contradiction.”

Al-Abharī said:

“Objection: He says, ‘Causal action upon a possible being must occur either in the state of existence, in the state of nonexistence, or in neither state.’

We reply: Why could it not occur in the state of existence?

He says, ‘Causal action in the state of existence amounts to bringing into existence what already exists and producing what has already been produced.’

We reply: We do not concede this. That would be so only if the agent imparted a second existence, which is not the case. Rather, causal action means that the effect exists by virtue of its cause’s existence.

The effect may exist perpetually by virtue of its cause’s existence. The proof that causal action occurs in the state of existence is that, otherwise, it would occur in the state of nonexistence, since there can be no intermediate state between existence and nonexistence. The latter alternative is false, because causal action in the state of nonexistence would entail the simultaneous presence of existence and nonexistence, which is impossible.”

He said:

“As for his statement, ‘If bodies were eternal, they would have been either moving or stationary from eternity,’ we reply: Why could they not have been moving?

He says, ‘One and the same thing would necessarily be both preceded by something else and not preceded by anything else.’

We reply: We do not concede this, because what is preceded by something else is the motion, whereas what is not preceded by anything else is the body.