sonicandfffan
Warlord
Right there seems to be some confusion as to whether tourism or culture defends against ideology pressure. The answer to this is both are required to defend.
Click the tourism button at the top of the screen. This gives you the following screen:
You can also choose from the dropdown menu to pick other Civs and see their influence over everyone, including you:
How tourism works
Firstly you need to know how tourism works. Your tourism is your offensive culture. Each turn your current level of tourism (after modifiers) is added to all Civilizations who you have met. Your total tourism for that Civ is then compared to the total amount of culture that civ has generated. For example your tourism is +10 after 10 turns your tourism for that Civ will be 100. If that Civ's culture is 10,000 your percentage will be 1% (since 100 is 1% of 10,000)
Levels of influence
Most importantly for ideologies, notice the levels of influence. These change once your tourism reaches a certain percentage of a Civ's culture:
0: Unknown: Less than 10%
1: Exotic: 10% - 30%
2: Familiar 30% - 60%
3: Popular: 60% - 100%
4: Influential: 100% - 200%
5: Dominant: More than 200%
The conditions for a cultural victory are that your level reaches influential with every Civ.
Notice the number before each level. Let's call this the influence level
So how does ideological influence work?
Well while your tourism is being pitted against the culture of other civilizations, their tourism is being pitted against your culture. If you click the drop down menu in the above tourism screen you can see how influential these Civs are against your Civ.
To calculate that Civ's ideological pressure over you (or yours over them) you do the following:
Ideology pressure = Other Civ's influence level on you - Your influence level on them
So if you have high culture and everyone is unknown to you but you have no tourism output, your Civ will be fine. Likewise if everyone is exotic to you but you are familiar with everyone else, your Civ will be fine.
If the number is negative, your civ will be influencing the other civ. If it is positive they will be influencing you.
For example In the above screenshot Brazil is familiar with Spain and Spain are unknown to Brazil. So Spain's ideology pressure over Brazil will be 0-2=-2 so Brazil will have 2 pressure over Spain with its ideology (and Spain will have 0 pressure over Brazil).
Of course, it doesn't quite end there, there are three ideologies. Let's say your Civ is following ideology A. Calculate the ideology pressure for every Civ following ideology A and add the positive numbers together (if you influence the other civs then this counts as a 0 for these formulas). This is your ideology defense.
Ideology defense = (Sum of positive ideology pressures from ideology A)
Note if ideology A is the world ideology then the formula becomes:
Ideology defense = (Sum of positive ideology pressures from ideology A) + 2
For example If I was Spain and I chose Autocracy, if Brazil has 2 pressure over me (as above) and France has 3 pressure over me and they both have Autocracy then my Ideology defense is 5. If Autocracy becomes the world ideology then Spain's Ideology defence is 7.
The total unhappiness level your Civ is subject to from ideologies X and Y that your civ isn't following is given as follows.
Total unhappiness level = (Sum of positive ideology pressures from ideology X) + (Sum of positive ideology pressures from ideology Y) - (Ideology Defense)
For example: If Spain was as above and had ideology defense of 5 but Austria (Freedom) has a pressure of 4 and the Maya (Freedom) has a pressure of 3 then the total unhappiness level is 4+3-5 =2. Then Spain would have dissidents thanks to Freedom. If Autocracy becomes the world ideology then the total ideology pressure returns to 0 and Spain is content.
For example 2: Spain's defense is 5 (as above). Freedom has a pressure of 4 and Order has a pressure of 2. Then the total will be 4+2-5=1 and you have an unhappiness level of 1 or dissidents.
For example 3: Suppose instead only you follow Freedom (defense =0), order has a pressure of 2 (i.e 2 civs have an ideology pressure of 1 over you - their influence over your civ is one level above your level over theirs) and autocracy has a pressure of 1. Then your total unhappiness level will be 3 which will be Civil Resistance
The unhappiness levels
0: Content (0 change)
1-2: Dissidents (1
per city or 1
per 10 population, whichever is more)
3-4: Civil Resistance (2
per city or 1
per 5 population, whichever is more)
5+: Revolutionary Wave (4
per city or 1
per 3 population, whichever is more)
Note revolutionary wave is the highest level of influence a Civ will reach. You can be at an unhappiness level of 7 and still be revolutionary wave, see the following image:
How to avoid happiness penalties
-The most effective way is to make your ideology the world ideology. It provides 2 defense for your Civ against other ideologies and 2 offense to convince other Civs to change. Also note that if a civ is hugely influential over everyone it will have no ideology defense (since nobody is influencing that Civ with an ideology) so it will experience dissidents from a world ideology. You can pay other Civs to vote for you in the world congress to get this through.
-Increase your culture to reduce the influence level other civs have over you
-Increase your tourism to increase the influence level you have over other civs
-Choose the same ideology as the Civ most influential over you to get some ideology defense
-Remove the most influential Civ from the game through warfare.
-Use the great writer's ability to boost your Civ's culture
-Use the great musician's ability to boost your tourism with an influential civ
What won't work:
-Removing a few cities from an influential Civ (their CPT might drop allowing you to increase your tourism influence over them, but their culture total won't drop). Also this will only affect one civ directly, whereas pressure will be coming from all directions.
-Increasing your pressure over Civs you already influence, it is only those who influence you that matter. If they convert you won't get any benefit either because they don't influence you, but them converting might cause them to influence Civs who influence you and cause them to switch, so it can help indirectly.
Click the tourism button at the top of the screen. This gives you the following screen:
Spoiler :

You can also choose from the dropdown menu to pick other Civs and see their influence over everyone, including you:
Spoiler :

How tourism works
Firstly you need to know how tourism works. Your tourism is your offensive culture. Each turn your current level of tourism (after modifiers) is added to all Civilizations who you have met. Your total tourism for that Civ is then compared to the total amount of culture that civ has generated. For example your tourism is +10 after 10 turns your tourism for that Civ will be 100. If that Civ's culture is 10,000 your percentage will be 1% (since 100 is 1% of 10,000)
Levels of influence
Most importantly for ideologies, notice the levels of influence. These change once your tourism reaches a certain percentage of a Civ's culture:
0: Unknown: Less than 10%
1: Exotic: 10% - 30%
2: Familiar 30% - 60%
3: Popular: 60% - 100%
4: Influential: 100% - 200%
5: Dominant: More than 200%
The conditions for a cultural victory are that your level reaches influential with every Civ.
Notice the number before each level. Let's call this the influence level
So how does ideological influence work?
Well while your tourism is being pitted against the culture of other civilizations, their tourism is being pitted against your culture. If you click the drop down menu in the above tourism screen you can see how influential these Civs are against your Civ.
To calculate that Civ's ideological pressure over you (or yours over them) you do the following:
Ideology pressure = Other Civ's influence level on you - Your influence level on them
So if you have high culture and everyone is unknown to you but you have no tourism output, your Civ will be fine. Likewise if everyone is exotic to you but you are familiar with everyone else, your Civ will be fine.
If the number is negative, your civ will be influencing the other civ. If it is positive they will be influencing you.
For example In the above screenshot Brazil is familiar with Spain and Spain are unknown to Brazil. So Spain's ideology pressure over Brazil will be 0-2=-2 so Brazil will have 2 pressure over Spain with its ideology (and Spain will have 0 pressure over Brazil).
Of course, it doesn't quite end there, there are three ideologies. Let's say your Civ is following ideology A. Calculate the ideology pressure for every Civ following ideology A and add the positive numbers together (if you influence the other civs then this counts as a 0 for these formulas). This is your ideology defense.
Ideology defense = (Sum of positive ideology pressures from ideology A)
Note if ideology A is the world ideology then the formula becomes:
Ideology defense = (Sum of positive ideology pressures from ideology A) + 2
For example If I was Spain and I chose Autocracy, if Brazil has 2 pressure over me (as above) and France has 3 pressure over me and they both have Autocracy then my Ideology defense is 5. If Autocracy becomes the world ideology then Spain's Ideology defence is 7.
The total unhappiness level your Civ is subject to from ideologies X and Y that your civ isn't following is given as follows.
Total unhappiness level = (Sum of positive ideology pressures from ideology X) + (Sum of positive ideology pressures from ideology Y) - (Ideology Defense)
For example: If Spain was as above and had ideology defense of 5 but Austria (Freedom) has a pressure of 4 and the Maya (Freedom) has a pressure of 3 then the total unhappiness level is 4+3-5 =2. Then Spain would have dissidents thanks to Freedom. If Autocracy becomes the world ideology then the total ideology pressure returns to 0 and Spain is content.
For example 2: Spain's defense is 5 (as above). Freedom has a pressure of 4 and Order has a pressure of 2. Then the total will be 4+2-5=1 and you have an unhappiness level of 1 or dissidents.
For example 3: Suppose instead only you follow Freedom (defense =0), order has a pressure of 2 (i.e 2 civs have an ideology pressure of 1 over you - their influence over your civ is one level above your level over theirs) and autocracy has a pressure of 1. Then your total unhappiness level will be 3 which will be Civil Resistance
The unhappiness levels
0: Content (0 change)
1-2: Dissidents (1


3-4: Civil Resistance (2


5+: Revolutionary Wave (4


Note revolutionary wave is the highest level of influence a Civ will reach. You can be at an unhappiness level of 7 and still be revolutionary wave, see the following image:
Spoiler :

How to avoid happiness penalties
-The most effective way is to make your ideology the world ideology. It provides 2 defense for your Civ against other ideologies and 2 offense to convince other Civs to change. Also note that if a civ is hugely influential over everyone it will have no ideology defense (since nobody is influencing that Civ with an ideology) so it will experience dissidents from a world ideology. You can pay other Civs to vote for you in the world congress to get this through.
-Increase your culture to reduce the influence level other civs have over you
-Increase your tourism to increase the influence level you have over other civs
-Choose the same ideology as the Civ most influential over you to get some ideology defense
-Remove the most influential Civ from the game through warfare.
-Use the great writer's ability to boost your Civ's culture
-Use the great musician's ability to boost your tourism with an influential civ
What won't work:
-Removing a few cities from an influential Civ (their CPT might drop allowing you to increase your tourism influence over them, but their culture total won't drop). Also this will only affect one civ directly, whereas pressure will be coming from all directions.
-Increasing your pressure over Civs you already influence, it is only those who influence you that matter. If they convert you won't get any benefit either because they don't influence you, but them converting might cause them to influence Civs who influence you and cause them to switch, so it can help indirectly.