# Relationship between hierarchy problem and higgs fine tuning?

I often hear of hierarchy problem being used synonymous with Higgs fine tuning (esp with regards with motivations for SUSY). What exactly is the relationship between the two problems? As I understand it, the quadratic divergence from the Higgs self coupling means you need a lot of fine tuning to get a low Higgs mass.

However, the hierarchy problem is the following: Why is the electroweak scale (where W/Z physics is important, roughly 1 TeV) SO much less than the Planck scale.

So, why is this in effect, the same problem as the higgs fine tuning?

So whenever you have something like a particle of mass $\Lambda$, its loops connected to the Higgs in some way shift the squared Higgs mass by terms of order $\Lambda^2$. Clearly, the effects connected with the highest value of $\Lambda$ are the most important, dominant ones. The Planck scale, or slightly beneath the Planck scale, is the highest energy scale at which quantum field theory of some sort should hold. That's why it's legitimate to substitute the effects from this scale to $\Lambda^2$ and say that they contribute $m_{Pl}^2$ to the squared Higgs mass. Other effects contribute as well and the question is why the total Higgs mass is so much smaller – the squared Higgs mass is $10^{30}+$ times smaller than the squared Planck mass.
One can't believe any quantum field theory at energy scales exceeding the Planck scale because that's where gravity becomes strong and one needs a full theory of quantum gravity – probably synonymous with string/M-theory – which is strictly speaking not just a quantum field theory and the naive "addition of $\Lambda^2$" and similar QFT wisdom can't be relied upon.