How will you justify that ice , water and steam are the three states of a substance and not different substances?

The constituent particle in ice, water and steam is water molecules.The only difference is the space in between the particles. In case of steam water molecules are far apart. while in liquid water they are closer but the closest in case of ice. We can get the water from ice or steam from ice and vice-versa by changing the temperature only. This signifies that they are 3 states of matter as solid, liquid and gas.