SQlite difference between FALSE and 0

these both statements seem to make a difference, but I do not yet get why:

ALTER TABLE FOO ADD COLUMN DELETED BOOLEAN NOT NULL DEFAULT FALSE

seems to behave differently than:

ALTER TABLE FOO ADD COLUMN DELETED BOOLEAN NOT NULL DEFAULT 0

can anyone shed some light on this - I thought FALSE is 0 and TRUE is 1 - but this boolean seems to have >= 4 states:

➜  ~  sqlite3               
SQLite version 3.8.7.4 2014-12-09 01:34:36
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database.
sqlite> CREATE TABLE FOO ( id INTEGER );sqlite> INSERT INTO FOO ( id ) VALUES (1);
sqlite> select * from FOO;
1
sqlite> ALTER TABLE FOO ADD COLUMN DELETED BOOLEAN NOT NULL DEFAULT FALSE;sqlite> select * from FOO;
1|FALSE
sqlite> ALTER TABLE FOO ADD COLUMN DELETED2 BOOLEAN NOT NULL DEFAULT 0;
sqlite> select * from FOO;
1|FALSE|0
sqlite> ALTER TABLE FOO ADD COLUMN DELETED3 BOOLEAN NOT NULL DEFAULT TRUE;
sqlite> select * from FOO;
1|FALSE|0|TRUE
sqlite> ALTER TABLE FOO ADD COLUMN DELETED4 BOOLEAN NOT NULL DEFAULT 1;
sqlite> select * from FOO;
1|FALSE|0|TRUE|1

sqlite> select * from FOO WHERE DELETED;
sqlite> select * from FOO WHERE DELETED2;
sqlite> select * from FOO WHERE DELETED3;
sqlite> select * from FOO WHERE DELETED4;
1|FALSE|0|TRUE|1