Immanuel Kant is considered the founder of Deontological Ethics, a theory that emphasizes the importance of duty and moral obligation.

The categorical imperative is the central principle of Kantian ethics, which states that one should act only according to the maxim by which one can, at the same time, will that it should become a universal law.

Always telling the truth is an example of a categorical imperative because it is a moral principle that can be universally applied without contradiction.

A hypothetical imperative is a conditional statement that depends on a particular goal or desire, while a categorical imperative is an unconditional statement that applies to all rational beings regardless of their desires.

Kantian ethics has been criticized for being too abstract and impractical, too rigid and inflexible, and for ignoring the importance of consequences.

John Rawls developed the concept of the 'veil of ignorance' as a way to address the problem of bias in moral decision-making.

The 'veil of ignorance' is a hypothetical situation in which people are unaware of their own personal characteristics and circumstances, such as their social class, race, gender, or wealth. This is intended to help people make decisions that are fair and impartial.

A moral dilemma is a situation in which a person is faced with a choice between two or more actions, each of which has morally significant consequences.

Consequentialism has been criticized for being too focused on the end result and ignoring the means used to achieve it, for being too subjective and depending on the individual's interpretation of the consequences, and for leading to morally unacceptable outcomes in certain situations.

Immanuel Kant argued that the only intrinsically good thing is a good will, which is a will that is motivated by duty and moral obligation.

A perfect duty is an obligation that must be fulfilled without exception, such as the duty not to kill or steal. An imperfect duty is an obligation that can be fulfilled in a variety of ways, such as the duty to help those in need.

Telling the truth is an example of a perfect duty because it is an obligation that must be fulfilled without exception.

Helping those in need, being polite, and returning a borrowed book are all examples of imperfect duties because they are obligations that can be fulfilled in a variety of ways.

An act is a specific action, while a maxim is a general rule of conduct. Acts are motivated by desire, while maxims are motivated by duty. Acts are observable, while maxims are internal and subjective.

Always telling the truth is an example of a maxim because it is a general rule of conduct that can be applied to a variety of situations.