Disposition is your character's stance on law vs chaos. There are three stances on this axis.

Justified - Your character favors law, order, and justice.
Neutral - Your character is indifferent to law vs chaos.
Lawless - Your character favors freedom, individualism, and does not let laws dictate their actions.

Depending on your stance, you will have access to different rewards. This is reflected by quests, dialogues, and also activities.

Justified characters have access to free room & board at all inns. They'll also generally get paid decently for their decisions and actions.

Neutral characters typically can get a good selection of rewards for quests based on their decisions. They can buy illegal mixtures from dealers as well.

Lawless characters will gain access to black market shops, illegal mixture dealers, and sometimes get some of the best rewards for quests - even if their methods are unorthodox.

Standing: -infinity to 0 is considered lawless, 1 to 100 is considered neutral, and 101 to infinity is considered justified.

Different actions will affect this score in varying degrees.

Soul is a representation of your character's heart and where it stands on good vs evil.

Bright soul characters are good, selfless, and compassionate.
Dim soul characters are in the middle. They sometimes will help others, and sometimes not.
Black soul characters are evil, selfish, and hold no value for the well-being of others.

Again, based on your stance, you'll have access to different things.

Bright soul characters have access to temple and church shops which hold a wide variety of different goods and some of the best protection against awful maladies encountered in the game world. They also will get paid decently and usually most other characters in the game react well to this.

Dim soul characters will get access to temple and church shops as well, but they'll have more variety in their rewards from quests and certain situations as well.

Black soul characters gain access to henchmen. Henchmen are lesser companions with slightly reduced stats, but they are infinite. You may only have one at a time, but you can always get another. They can reach level 25 and can use any type of equipment. They are essentially cannon fodder as they also have a very high target chance for enemies.

Standing: -infinity to 0 is considered black, 1 to 100 is considered dim, and 101 to infinity is considered bright.

Different actions will affect this score in varying degrees.

Your standing on the axes will shift constantly while playing. Nearly every single decision and action you make will influence them in varying degrees. You can start as one alignment and end up as the complete opposite or anything in between.

You can view your current standings by accessing the character record item in the plot section of your inventory and going to overview.

Given that there are 2 axes and 3 stances in each, that means there are essentially a total of 9 different playstyles based on alignment alone. You can always benefit from at least 2 rewards/bonuses - 1 from disposition, and 1 from soul.