If everything is fated, why did Chrysippus say we are still responsible?

Chrysippus's answer was a cylinder and a cone. The Stoics were determinists about causation: every event is the result of a cause or chain of causes, so that everything that happens is determined by preceding causes. Yet they wanted to preserve moral responsibility, by defending a version of compatibilism.

Critics pressed two worries. The first is the "lazy argument": if all my actions and their consequences are predetermined, there is no point in acting at all. Why call the doctor when ill, if it is determined that the doctor will come? Chrysippus replied that some events are co-fated, part of the same causal chain so that they cannot be separated: the doctor will not come if she is not called, so calling is not pointless. The second worry is that actions caused by earlier events are not in my power, so I am not responsible for them.

Here the cylinder and cone come in. According to Cicero, Chrysippus said a cylinder and a cone cannot begin to move without a push, but once pushed it is through their own nature that the cylinder rolls and the cone spins. Likewise, although the impression encountered will print its appearance on the mind, assent will be in our power. The push is not the whole cause: the nature of the thing pushed matters too. Rational creatures are responsible for their acts of assent, though not for the impressions they receive.

Does that really escape determinism? The Stanford Encyclopedia itself adds a pointed note: given the push and its own nature, each solid could not do otherwise than it does.