Personal Assent
There are three basic positions that can be taken with respect to personal assent: assent, denial, and indifference. For example, consider the proposition, "It will rain tomorrow." We have three basic options: assent to the proposition and assert that it is true; deny the proposition and assert that it is false; or take up a stance of indifference (or ignorance) and neither assert that it is true nor that it is false.
Ecclesial Assent
There are three basic positions that the Church takes up with respect to corporate assent, and they correlate to the above three positions. They are: dogma, heresy, and theological opinion. Dogmas require assent, heresies require denial, and theological opinions require neither assent nor denial. For example, take the proposition, "Jesus Christ is fully God and fully man." We have three basic options: assent, denial, and indifference. Since this proposition is a dogma of Christianity, assent is required, denial is heresy, and indifference is not an option.
A dogma is something that is essential to Christianity, and a heresy is something that is contradictory to Christianity. The logical relation of dogma and heresy to Christianity is as follows:
*At least implicitly.
Erroneous Modern Tendencies
In modernity there have been two erroneous and common tendencies. The first is religious indifferentism. This is the view that there are no dogmas, there are no heresies, everything is a matter of theological opinion, and people can believe whatever they want while still calling themselves "Christian." The problem with this error at the most general level is that the religion becomes contentless, without form or substance. If people can believe whatever they want while still calling themselves "Christian," then the name "Christian" becomes meaningless. The more specific problem is that the Good News becomes emptied of substance.
The second erroneous modern tendency is a kind of progressive reversal. This is the view that some things which were previously dogmas are now heresies, and some things which were previously heresies are now dogmas. The problem with this error at the most general level is that it constitutes institutional self-contradiction. The more specific problem is that the Good News is undermined and anti-evangelization occurs, where "good is called evil" (Isaiah 5:20). A third problem is that Christianity becomes nothing more than a vehicle for the passing doctrines of the day (Ephesians 4:14).
In order to avoid these erroneous tendencies we must ask ourselves, first, what are our dogmas and heresies? What things are essential to the Christian faith, and what things are incompatible with the Christian faith? Second, we must ask ourselves whether the dogmas and heresies that we hold today are consistent with the dogmas and heresies that our Christian ancestors held. We must ask, ultimately, whether we are part of the same religion that Jesus Christ founded 2000 years ago.
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There are three basic positions that can be taken with respect to personal assent: assent, denial, and indifference. For example, consider the proposition, "It will rain tomorrow." We have three basic options: assent to the proposition and assert that it is true; deny the proposition and assert that it is false; or take up a stance of indifference (or ignorance) and neither assert that it is true nor that it is false.
Ecclesial Assent
There are three basic positions that the Church takes up with respect to corporate assent, and they correlate to the above three positions. They are: dogma, heresy, and theological opinion. Dogmas require assent, heresies require denial, and theological opinions require neither assent nor denial. For example, take the proposition, "Jesus Christ is fully God and fully man." We have three basic options: assent, denial, and indifference. Since this proposition is a dogma of Christianity, assent is required, denial is heresy, and indifference is not an option.
A dogma is something that is essential to Christianity, and a heresy is something that is contradictory to Christianity. The logical relation of dogma and heresy to Christianity is as follows:
1. If someone is a Christian, then they must assent to the dogmas.*
2. If someone formally assents to a heresy, then they are no longer Christian.
2. If someone formally assents to a heresy, then they are no longer Christian.
*At least implicitly.
Erroneous Modern Tendencies
In modernity there have been two erroneous and common tendencies. The first is religious indifferentism. This is the view that there are no dogmas, there are no heresies, everything is a matter of theological opinion, and people can believe whatever they want while still calling themselves "Christian." The problem with this error at the most general level is that the religion becomes contentless, without form or substance. If people can believe whatever they want while still calling themselves "Christian," then the name "Christian" becomes meaningless. The more specific problem is that the Good News becomes emptied of substance.
The second erroneous modern tendency is a kind of progressive reversal. This is the view that some things which were previously dogmas are now heresies, and some things which were previously heresies are now dogmas. The problem with this error at the most general level is that it constitutes institutional self-contradiction. The more specific problem is that the Good News is undermined and anti-evangelization occurs, where "good is called evil" (Isaiah 5:20). A third problem is that Christianity becomes nothing more than a vehicle for the passing doctrines of the day (Ephesians 4:14).
In order to avoid these erroneous tendencies we must ask ourselves, first, what are our dogmas and heresies? What things are essential to the Christian faith, and what things are incompatible with the Christian faith? Second, we must ask ourselves whether the dogmas and heresies that we hold today are consistent with the dogmas and heresies that our Christian ancestors held. We must ask, ultimately, whether we are part of the same religion that Jesus Christ founded 2000 years ago.
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Some might claim that Christianity, or religion, should not be propositional. I think it should be and needs to be since humans are rational creatures, but that aside, the content of dogmas and heresies need not always be theoretical. Presumably the schema could also be analogously applied to actions, where some actions are required ("love thy neighbor"), some are prohibited ("thou shalt not commit adultery"), and some are indifferent. In the past there were certain grave sins that cut one off from the Church, and which required a formal period of public penance before reconciliation could occur. The two modern errors therefore apply equally to actions, and those who are more action-oriented could recast this OP in light of practical actions which are encouraged or prohibited.