logical deduction - What is 5 equal to?

Can you find what corresponds to 5?

If: $$1=5$$ $$2=6$$ $$3=7$$ $$4=8$$

then, $$5=?$$

Note: the answer is not 9.

Answer

Is the answer simply

1, due to symmetry (thanks for the correction, @Peter!!) of the equals sign?