Question about measurement of half-cell potential

I am reading about electrochemical cells from the chapter: Electrochemical cells, Batteries and Fuel cells in the book 'Physical Chemistry' by Thomas Engel and Philip Reid, 3rd edition.


I came across the following paragraph and I want to know if my understanding of this paragraph is correct or not?


The paragraph is about $\ce{Zn}$ elctrode partially immersed in an aqueous solution of $\ce{ZnSO4}$




---


Paragraph: Can we measure $\Phi$( half-cell potential) directly? Let us assume we can carry out the measurement using two chemically inert **Pt** wires as probes. One **Pt** wire is placed on **Zn** electrode and the second **Pt** wire is placed in the $\ce{ZnSO4}$ solution. However, the measured voltage is the difference in electrical potential between a **Pt** wire connected to a zinc electrode in $\ce{ZnSO4}$ solution and a **Pt** electrode in a $\ce{ZnSO4}$ solution, which is not what we want.




---


My question is whether the author wants to say that the second platinum wire will act as an electrode in zinc sulphate solution and hence the potential difference measured will be between zinc electrode and platinum wire which won't be the potential difference between zinc electrode and zinc sulphate solution?


Any help is appreciated.
Thanks!




Absolute measurements of half-potentials have no sense. They do not exist. They can be measured with respect to something, like for example the hydrogen electrode. It is similar to measuring the absolute altitude. The absolute altitude does not exist. The altitude is measured with respect to the sea level. The altitude cannot have an absolute value.


 0