AEM log Level 0 to level 3 meaning

The log levels are as follows:

0	Fatal error	The action has failed, and the installer cannot proceed.
1	Error	The action has failed. The installation proceeds, but a part of AEM WCM was not installed correctly and will not work.
2	Warning	The action has succeeded but encountered problems. AEM WCM may or may not work correctly.
3	Information	The action has succeeded.