Por tanto vs Por lo tanto
I have noticed several times these "two" and "three" words on different articles. Could anyone tell me when we should use "Por tanto" and when to use "Por lo tanto"
Actually, "por lo tanto" and "por tanto" are two different phrases. "Por lo tanto," indeed, does mean "therefore." "Por tanto," on the other hand, means "regarding that."
This sentence in a Spanish newspaper article about the death of bin Laden will hopefully illustrate my point.
Había, por tanto, poco que ganar en la distribución de esas imágenes: In regards to the revealing the pictures, there would have been little gain.
The sentence before that was:
Entre quienes aceptan la palabra del Gobierno norteamericano, respaldada por los científicos que realizaron una prueba de ADN que identifica el cadáver de Bin Laden con un 99,9% de margen de acierto, la visión de las fotos no aporta más que una recreación de una extraordinaria violencia. Among those who accept the the word of the US government, backed by the scientist who used DNA evidence to identify the body of Bin Laden with 99.9% accuracy, seeing the photos would contribute no more than further conflict."
"Por tanto" connected the phrase "showing the photograph" between both sentences.
I know my explanation was long, but I hope I cleared up any confusion.
I found this entry in the dictionary, and it looks like you can use both as "therefore."
por (lo) tanto = therefore
Another dictionary says that "por lo tanto" means "therefore."
I'm sure others will come along and give you a better explanation as to the differences between the two phrases.
The near literal translations would be:
Por tanto: for which
Por lo tanto: for the which
Both mean almost the same thing, just as they would in English. My dictionary shows them as synonyms of each other (along with a number of other phrases). You can use them interchangeably. The difference is very subtle, if it exists at all.
The drae definitions are slightly different: link