Question

Shouldn't pressure be dependent on volume?

Answer 1

If you are talking about gases, pressure does depend on volume. From ideal gas law, we have

$PV = nRT$

At constant temperature, PV = constant.
So Pressure varies inversely with volume.

Answer 2

If you are talking about gases, pressure does depend on volume. From ideal gas law, we have

$\bf PV = nRT$

At constant temperature, PV = constant.

So, Pressure varies inversely with volume.