Thoughts about the relative importance of logic and physics in Stoicism
“physics played a much less important role than logic in the Stoic philosophy."
- Samuel Sambursky, Physics of the Stoics, p. vii.
In my opinion, this is an incredibly important reminder.
Sometimes there seems to be a tendency to think that we must see the world as the ancient Stoics saw it to achieve the kind of wisdom the Stoics were talking about.
Obviously, though, it is not this or that theory about nature that makes us wise (as wise as we can be) but a well-justified theory. And the implication of that is, of course, that if our favorite theory - or any element of it - turns out to be wrong, that theory or that element of the theory has to go. Wisdom to a Stoic does only imply assuming that everything is determined by fate, for example, if that assumption is firmly believed to be true.
And the implication of this is, of course, that Stoic ethics is whichever theory about ethics we think follows from our theory of the world in general.
What Seneca is praising in this quote is not a particular theory about the world but the act of thinking about the world.
"I myself give thanks to nature whenever I see her not in her public aspect, but when I have entered her more remote regions, when I am learning what the material of the universe is, who is its creator or guardian, what god is, whether he is totally focused on himself or sometimes takes notice of us too, whether he creates something every day or has created once and for all, whether he is part of the world or the world itself, whether even today he may make decisions and amend part of the law of fate, or whether it would be an impairment of his greatness and an admission of error to have made something that needed alteration. But the same course must necessarily seem right to him to whom only the best course can seem right, nor does that make him less free or powerful; for he himself is his own necessity. If I were not allowed access to these questions, it would not have been worth being born."
- Seneca, Natural Questions 1 (7), praefatio 3-4
This passage also shows us something more basic than what the Stoics thought the answers to those questions were. It shows us that a Stoic believed that those questions ought to be answered and that we need philosophy to answer them.