【Because】 , 【for】 , 【since】 , 【as】 , 【inasmuch】 【as】 are the chief causal conjunctions in English.

【Because】 assigns a cause or reason immediately and explicitly; 【as】 , I hid myself, 【because】 [= 【for】 the express reason that, or 【as】 caused to do so by the fact that] I was afraid; he must have passed this way, 【because】 [=owing to the specific fact that] there is no other road or 【because】 [= 【as】 is directly proved by the fact that] his footprints are here.

【For】 is a particle of less immediate reference than 【because】 ; it regards the statement to which it is subjoined 【as】 relatively independent and proceeds to adduce 【for】 it some ground, reason, evidence, proof, explanation, or justification; 【as】 , I hid myself, 【for】 [= 【as】 I may add by way of explanation] I was afraid; he must have passed this way, 【for】 [= 【as】 you may readily see] here are his footprints; I like him, 【for】 [=I ask, in justification of the fact] who can help it?

【Since】  is less formal and more incidental than 【because】 ; 【as】 assigns a reason even more casually than 【since】 ; each of them frequently begins its sentence; 【as】 , 【Since】 (or 【As】 ) I was afraid, I hid myself .

【Inasmuch】   【as】 assigns a reason in a somewhat concessive or qualified fashion; 【as】 , 【Inasmuch】 【as】 [=in view of, or considering, the fact that] I was afraid, I hid myself; I am ready to accept your proposal, 【inasmuch】 【as】 [=seeing that] I believe it is the best you can offer.