Answer
Just causes arise from the employee's own fault and are listed in Article 297 of the Labor Code: serious misconduct, wilful disobedience of lawful orders, gross and habitual neglect of duty, fraud or wilful breach of trust, commission of a crime against the employer or his representative, and other analogous causes. A dismissal for a just cause does not carry separation pay.
Authorized causes are business or health grounds not due to employee fault — installation of labor-saving devices, redundancy, retrenchment to prevent losses, and closure (Article 298), and disease (Article 299). Authorized-cause dismissals require written notice to the worker and to the DOLE at least one month in advance, and they carry separation pay.