An absolutist morality is one that considers something immoral regardless of consequence, situation, and circumstance. For example: "you should never ever lie, steal, rape, etc no matter what"
Some people claim an absolutist morality is lazy. Are there philosophies that defend an absolutist position?
A caveat and then an argument.
Caveat: Language is the symbolic representation of ideas, and exceptions can be imported into any symbolic representation. For example: suppose we had no word that meant "rape". What is rape? To rape is "to have sex, except for sex with consent". So the absolute statement, "never rape" is exactly identical to the conditional statement, "never have sex, except for sex with consent".
You can redefine conditionals to be absolutes simply defining a new term. "Never steal, except to preserve a life," can be "Never florbleblarp," where florbleblarp is the act of taking something that is not yours in a situation in which lives would not be saved by the taking.
You can also reframe conditionals as absolutes by appropriately thinking them through. We could replace "Never lie except..." with "never deprive a person of a truth that they might use virtuously". This simultaneously solves the problem of lying-by-omission to circumvent the absolute prohibition on lying, and the problem of "when the secret police knock on the door and demand to know if you have any persecuted minorities hiding in your attic."
In short: a deontological system is one which consists of rules, whether or not the symbolic representations of those rules include words like "if" or "except".
A consequentialist argument for being a deontologist: A system of morality is judged on its consequences. Therefore if deontological ethics generates, on average, better consequences than consequentialist ethics, one ought to act as though deontological ethics were correct, whether one is a consequentialist or a deontological ethicist.
Why might we expect an absolute morality to generate better consequences than a consequentialist morality?
Humans lack total knowledge of outcomes. Humans are extremely vulnerable to cognitive bias when it comes to predicting outcomes. Humans are extremely bad at doing accurate consequentialist calculus rapidly in their heads under stress; any attempt to try will usually lead to stalling until the chance to do the right thing has already come and gone. Even humans with plenty of time to think about something are pretty bad at not convincing themselves through specious arguments to do whatever provides the most short-term personal gratification and the least social stress.
Rule-based morality is resilient to cognitive biases specifically because it is indifferent to arguments about consequences. Absolute morality exports all the calculus to the level of society: an individual need not assess or even know the priors that led to the imperative, he or she has direct access to the conclusion in the form of the imperative. Absolute morality is accessible immediately under stress. Absolute morality, given time to think, is resilient against arguments to do whatever provides the most short-term personal gratification and even tends to have a prohibition against doing exactly that.
There are philosophers who believe stuff like this, and they definitely aren't lazy! It's quite a respectable position - philosophers like Christine Korsgaard, for example, follow this position, although instead of "absolute" they call it "deontology". But what's deontology? To start, there are 3 main umbrella-theories that are usually acknowledged in ethics:
What deontology refers to is still a matter of debate, but nobody would fault you for using the definition you described - roughly, it is an ethical system that considers moral actions to follow certain principles, as opposed to actions that have good consequences, which is a rough definition of consequentialism, or actions that reflect a virtuous character, which is a very simplistic definition of virtue-ethics. Deontology wants you to act out of duty and to follow rules regardless of your own interests.
The arguments for this are very complex, and there are lots of examples of deontologists across history. However, the prime example that's taught in phil. 101 classes is the "Categorical Imperative" of Immanuel Kant. Kant believed, among other things, that it was always wrong to lie and always wrong to murder because they violated his formula for ethical rules. The categorical imperative is a very complex argument that stems from Kant's other principles, but a basic run-down can be found at these sources.
https://plato.stanford.edu/entries/kant-moral/
https://www.youtube.com/watch?v=8bIys6JoEDw
If you want more complex arguments (usually the intros to Kant's moral philosophy don't actually cover WHY he believes in the categorical imperative), please feel free to comment and ask me.
