Logical absolutes can be bound by time. So the law of identity might state that an apple is an apple. I might state that this apple in my hand is an apple and it would either be true or false by the law of excluded middle, in this case true. Then the law of non-contradiction would mean that if someone said my apple was an orange that their statement and my statement cannot both be true, so in this case my statement was true. Now imagine I eat the apple and digest it and excrete it as waste which is absorbed back into the earth. The truth of the prior statement of the law of identity is no longer true although it once was. The apples molecules have been spread out and chemically altered, it is no longer an apple. Also my statements about the apple which were once true are no longer true.