I don't know if this equation is possible in the physical world, but if it is, Sage can compute the answer.
I assume that by "dimension" you mean "volume", by "physical body" you mean "mass", and by "vibration speed" you mean "frequency". Then Sage can solve the dimensional equation for $S(2)$:
sage: s2 = var('s2')
sage: eq = units.volume.liter == (s2*units.amount_of_substance.mole^2 + units.mass.kilogram)/units.frequency.hertz
sage: eq.solve(s2)
[s2 == (hertz*liter - kilogram)/mole^2]
Hence "Soul", applied to "conscious & subconscious", is measured in $$\frac{(\mathrm{Hz}*\mathrm{m}^3 - \mathrm{kg})}{\mathrm{moles}^2}.$$ Not a very nice dimension, if you want my opinion.
Do you have more information on the function "Soul"? Is it linear?