Reply Obj. 1:  Disposition implies a certain order, as stated above (A. 1, ad 3).  Wherefore a man is not said to be disposed by some quality except in relation to something else.  And if we add “well or ill,” which belongs to the essential notion of habit, we must consider the quality’s relation to the nature, which is the end.  So in regard to shape, or heat, or cold, a man is not said to be well or ill disposed, except by reason of a relation to the nature of a thing, with regard to its suitability or unsuitability.  Consequently even shapes and passion-like qualities, in so far as they are considered to be suitable or unsuitable to the nature of a thing, belong to habits or dispositions:  for shape and color, according to their suitability to the nature of thing, concern beauty; while heat and cold, according to their suitability to the nature of a thing, concern health.  And in this way heat and cold are put, by the Philosopher, in the first species of quality.

Wherefore it is clear how to answer the second objection:  though some give another solution, as Simplicius says in his Commentary on the Predicaments.

Reply Obj. 3:  This difference, “difficult to change,” does not distinguish habit from the other species of quality, but from disposition.  Now disposition may be taken in two ways; in one way, as the genus of habit, for disposition is included in the definition of habit (Metaph. v, text. 25):  in another way, according as it is divided against habit.  Again, disposition, properly so called, can be divided against habit in two ways:  first, as perfect and imperfect within the same species; and thus we call it a disposition, retaining the name of the genus, when it is had imperfectly, so as to be easily lost:  whereas we call it a habit, when it is had perfectly, so as not to be lost easily.  And thus a disposition becomes a habit, just as a boy becomes a man.  Secondly, they may be distinguished as diverse species of the one subaltern genus:  so that we call dispositions, those qualities of the first species, which by reason of their very nature are easily lost, because they have changeable causes; e.g. sickness and health:  whereas we call habits those qualities which, by reason of their very nature, are not easily changed, in that they have unchangeable causes, e.g. sciences and virtues.  And in this sense, disposition does not become habit.  The latter explanation seems more in keeping with the intention of Aristotle:  for in order to confirm this distinction he adduces the common mode of speaking, according to which, when a quality is, by reason of its nature, easily changeable, and, through some accident, becomes difficultly changeable, then it is called a habit:  while the contrary happens in regard to qualities, by reason of their nature, difficultly changeable:  for supposing a man to have a science imperfectly, so as to be liable to lose it easily, we say that he is disposed to that science, rather than that he has the science.  From this it is clear that the word “habit” implies a certain lastingness:  while the word “disposition” does not.