To find the value of [tex]\( S^{-1}(0) \)[/tex], we need to determine the day on which Socrates worked 0 hours. Let’s look at the hours worked by Socrates for each day:
[tex]\[
\begin{array}{|l|r|r|r|r|r|}
\hline & \text{Mon} & \text{Tues} & \text{Wed} & \text{Thurs} & \text{Fri} \\
\hline
\text{Socrates} & 1 & 2 & 3 & 4 & 0 \\
\hline
\end{array}
\][/tex]
We observe the following:
- On Monday, Socrates worked 1 hour.
- On Tuesday, Socrates worked 2 hours.
- On Wednesday, Socrates worked 3 hours.
- On Thursday, Socrates worked 4 hours.
- On Friday, Socrates worked 0 hours.
From these observations, we see that Socrates worked 0 hours on Friday.
Given the days of the week are indexed as follows:
- Monday is [tex]\( x = 0 \)[/tex]
- Tuesday is [tex]\( x = 1 \)[/tex]
- Wednesday is [tex]\( x = 2 \)[/tex]
- Thursday is [tex]\( x = 3 \)[/tex]
- Friday is [tex]\( x = 4 \)[/tex]
Since Socrates worked 0 hours on Friday, and Friday corresponds to [tex]\( x = 4 \)[/tex], we have:
[tex]\[ S^{-1}(0) = 4 \][/tex]
So, the answer is:
[tex]\[
\boxed{4}
\][/tex]