There are several "species" or types of soft and firm and people use the same words interchangeably to describe them even though they mean different things and different people may be more sensitive to one or the other. There is the

• Hand feel soft/firm that describes the surface "feel" of a mattress or the "hand feel".
• Pressure relieving soft/firm that describes the upper layers and the pressure relieving ability of the mattress and how well it forms a pressure relieving cradle that re-distributes weight.
• Deep support soft/firm that describes the firmness of the support layers and how far the heavier parts of the body sink down.
  Overall perception soft/firm that describes the more subjective overall feel of the mattress.

They are very different perceptions or "species" of softness and firmness that individuals are most sensitive to. When talking about the softness or firmness of a mattress ... it's important to know "which" softness or firmness you are referring to because the "overall impression" is not really specific enough to understand what is happening when you lie on a mattress '(although the softness of the comfort layers is probably the one that most people relate to ... at least initially)'.