natures conflicting (literally: overpowering each other) -- the nature of the body is to be drawn after the physical, while the nature of the soul is to be drawn after the spiritual. Each tries to overcome the other and wants to conquer the other, that it will be drawn after it, because each one needs the help of the other.

[natures] mutually antagonistic (literally: essences which are enhanced in conflicting ways) -- this yearns for physical delights and is enhanced by them, while this yearns for spiritual yearnings and is enhanced by them. Hence, they are enhanced in conflicting ways.

The Creator has implanted in his soul -- the Rambam writes in the Shemonei Perakim that: "even though the nefesh (human soul) is essentially one (i.e. not physically divisible. This is why it is invisible), nevertheless it has 5 "powers", namely, sustenance which allows [the organism] to grow (i.e. an underlying spiritual power which drives and animates the biological cells), feeling, imagination, awareness, and intellect. The intellect is the primary essence while the other powers are implanted by the Creator in order to guide the body, for without this, the body could not endure..." the Rambam ends off there: "and if a man uses all his powers except for the intellect, then it is all for nothing. And this is what scripture says: (Mishlei 19:2) "Also, that the soul be without knowledge is not good; and he that hastens with his feet sins".

without the lust for physical pleasures man would not procreate and the human race would become extinct.

This is the intellect and understanding, through them he will yearn for lofty spiritual things, not for the body and its pleasures, and he will desire to part from the body and this world, because it yearns for its root [in the higher worlds] as the nature of all things is to yearn for its root.

Hence, the lusts overpowered the intellect, for the intellect is likened to a poor youth [in scripture as in "better a poor and wise child than an old and foolish king who no longer knows to receive admonition" (Koheles 4:13)"], while the lusts, which are the yetzer hara (evil inclination) is a foolish elder, since he came before the yetzer tov [good inclination which starts to come after 13 years of age].

the intellect is a spiritual entity -- As written, "And He breathed into man the soul of life" (Bereishis 2:7), this is the soul which originates from the higher spiritual worlds. And it includes within it all the levels of the spiritual worlds. It has 248 spiritual limbs and 365 spiritual sinews. Therefore, the body was also created in this form, as a tailor who makes a garment like the measure of the man. The body which is physical matter from the ground, is mixed and synthesized from the four elements and their spiritual components. This is called the "foundation soul" (nefesh yesodit). On this, the intellect, or "neshama" abides. The intellect does not benefit from physical pleasures, therefore it has no support or ally in this world, and all of the worldly pleasures are against it. This nefesh (foundation soul) is called the "nefesh bahamit" (animal soul), and it is an intermediary between the physical body and the soul (intellect), as is well explained in the book "Shaarei Kedusha" (essential reading) and in the book of Moshe Alshich.

For the commandment is a lamp and the torah is light -- like a candle which dispels darkness and then one can see what to do, so too the torah enlightens a man, and then he will be able to use his understanding, and not be blinded [by the lusts].