No. Even though such claim is in Dirac's classical work it is not true.

See e.g. Hong-Ou-Mandel interference, when exactly two different photons interfere. For quotation of Paul Dirac, and some more analysis, see:

• Andrzej Dragan, Paweł Ziń, Interference of Fock states in a single measurement, arXiv:quant-ph/0703273v1

However, there is some truth in Dirac's claim - photon interferes only with it itself if you have only one detector to measure.

No. Even though such claim is in Dirac's classical work it is not true.

See e.g. Hong-Ou-Mandel interference, when exactly two photons interfere (they can be even from different sources). For quotation of Paul Dirac, and some more analysis, see:

• Andrzej Dragan, Paweł Ziń, Interference of Fock states in a single measurement, arXiv:quant-ph/0703273v1

However, there is some truth in Dirac's claim - photon interferes only with it itself if you have only one detector to measure.